MadModder

The Shop => Electronics & IC Programing => Topic started by: RobWilson on December 04, 2015, 03:59:23 PM

Title: Digital oscilloscope project/kit
Post by: RobWilson on December 04, 2015, 03:59:23 PM
Hi Lads


Being that time of year AGAIN when the nights are dark and cold I thought I would have a go at doing a bit electronics , still lots to learn lol ,any way I bought one of those wee oscilloscope projects ,I think mine is a knock off , any way it was fun to put together and it works .  :bugeye:

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100716_zpsl8lujemr.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100716_zpsl8lujemr.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100723_zpspswerstz.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100723_zpspswerstz.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100725_zpsxbkya2ul.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100725_zpsxbkya2ul.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100721_zpsh3t9uvye.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100721_zpsh3t9uvye.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100719_zpsmkptonxv.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100719_zpsmkptonxv.jpg.html)

Trace is noisy ,but it was only 15 delivered  :coffee:



Rob
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on December 04, 2015, 05:03:44 PM
Looks very good Rob...  :thumbup:
Got a link for where you bougt it?

Might get one meself...
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 04, 2015, 05:48:03 PM
Here you go mate http://www.banggood.com/DSO138-DIY-Digital-Oscilloscope-Kit-Electronic-Learning-Kit-p-969762.html      , Banggood   :Doh:

I think you can get them off of ebay too :thumbup:



Rob

Title: Re: Digital oscilloscope project/kit
Post by: PekkaNF on December 05, 2015, 04:44:52 AM
That looks pretty good.

No surface mounts to solder as I see?

Did you use all components from the kit? Is there immediate need to change, I'm pretty suspicious of the electrolytes and switches at that price range.

Are you going to mount it on anything or just save the hassle and use as it is?

Thanks for sharing.

OT:
 I have been thinking of buying an entry level digital scope, but haven't decided even price/speck range. There is always something I can imagine that cheap one would not do, but often the simplest will do.

Most often I'll measure few mV signals under 10 Mhz, but pretrigger would be nice. Almost as often I'll measure line voltage power supplies 240 or 400 AC and often "memory" and 2-4 channels would be nice, but triggering is fairly basic.

That would not do anything that well, but because it's so cheap it could do may things and even rigged for a specials.

Pekka
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 05, 2015, 05:54:50 AM
Hi Pekka



Quote
No surface mounts to solder as I see?

It depends on what kit comes ,some dont have the SMD soldered .

Quote
Did you use all components from the kit? Is there immediate need to change, I'm pretty suspicious of the electrolytes and switches at that price range.

I used all the components and hardware that came with the kit , I did test each part/component before soldering to the board , as the instructions advised to do . all was good.

Quote
Are you going to mount it on anything or just save the hassle and use as it is?

I am undecided on what to do at the moment , if I had a 3DP I would have a go at printing a case for it , but I don't as yet so I  may make a wee stand for it ,more to give it mass so the leads dont pull it around the bench.


Rob



Title: Re: Digital oscilloscope project/kit
Post by: Joules on December 05, 2015, 07:26:28 AM
I know a guy who can help you out there Rob   :thumbup:

A printed case, segmented coolant hose for the stand and a Mag base so you can clip it where its needed.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 05, 2015, 07:59:13 AM
I know a guy who can help you out there Rob   :thumbup:

A printed case, segmented coolant hose for the stand and a Mag base so you can clip it where its needed.

Thanks Joules  :thumbup: 


I will have to see what I can come up with  :smart: 


Rob
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on December 05, 2015, 07:59:49 AM
There are two options for construction.
1st is smd components pre mounted then just add the thru hole items or
2nd The micro is pre mounted, you add the smd passives and then the th components to complete construction.....

I got this info from the JYE website....they say that there are numerous copies floating around, not happy that their work has been plagiarised....
Title: Re: Digital oscilloscope project/kit
Post by: shipto on December 05, 2015, 05:18:59 PM
I like that it will make a reasonable mobile unit. Already put order in with daughter for Christmas  :D
Title: Re: Digital oscilloscope project/kit
Post by: Joules on December 06, 2015, 12:08:36 PM
Here you go Rob, have a think about a case you can't easily be machined.

(http://i7.photobucket.com/albums/y253/joulesbee/3D%20Prints/Blue%20Baron%20Art%20Work_zpszcquubsy.jpg) (http://s7.photobucket.com/user/joulesbee/media/3D%20Prints/Blue%20Baron%20Art%20Work_zpszcquubsy.jpg.html)

I have nick named this the "Wilson Ninja Turtle Scope", as the casing is very much like that of a turtle shell, recessed display and buttons, though I didn't spend anymore time on the buttons, but you get the idea.   Convert your three selector switches to rotary activation (disk with a slot in it below the knob)  Bit of trial and error should see it all worked out.   Rear half of the casing has enough room to accommodate a USB power pack for wireless operation.  Two halves screw together, it's just a doodle to get you thinking.    :dremel:

          Joules

Hmmm, looking at the 3D this end it could also represent an overfilled hot water bottle too.... :palm:
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 06, 2015, 03:12:27 PM
Quote
"Wilson Ninja Turtle Scope"


 :lol: :lol: :lol: I like it Joules  :beer:  ,

Quote
have a think about a case you can't easily be machined

There is allot of freedom with 3DP ,  that a complex shape to machine , yes it doable with a cnc mill but not everyone has one of those .  What modeling software are you working with Joules ? 


I have been thinking of maybe hydro dipping or even plating 3DP parts  .   


Cheers Rob 
Title: Re: Digital oscilloscope project/kit
Post by: Joules on December 06, 2015, 03:33:11 PM
The software I use here is Rhino, export's are STL to Simplify3D for printing.

(http://i7.photobucket.com/albums/y253/joulesbee/3D%20Prints/WNTS%20II_zpspfp2qyzi.jpg) (http://s7.photobucket.com/user/joulesbee/media/3D%20Prints/WNTS%20II_zpspfp2qyzi.jpg.html)

Better buttons and insets for the power and scope input.   Very easy to visualise ideas, such as sculpting out the rotary dial area to the outer edge so they are easier to access and rotate by 90 degree the knob grips.    8-) it's addictive.

Hydro dipping works, you just have to get a good surface finish on the prints (they wet sand well).  Electro plating kits exist but cost a ridiculous amount for what they are.  However it's not rocket science to do in the kitchen when the wife is out   :thumbup:

http://lnx.robotfactory.it/en/copperface-the-new-mini-galvanic-is-coming/
Title: Re: Digital oscilloscope project/kit
Post by: Joules on December 06, 2015, 03:44:56 PM
On the other hand, should you have an expired tortoise that could become your scope case and save all this 3D printing hassle    :lol:
Title: Re: Digital oscilloscope project/kit
Post by: tom osselton on December 06, 2015, 03:54:55 PM
Here is some copper conductive paint for $40.00

http://www.caswellplating.com/copper-conductive-paint-4oz.html
Title: Re: Digital oscilloscope project/kit
Post by: philf on December 06, 2015, 04:40:37 PM
....... yes it doable with a cnc mill but not everyone has one of those.....................

But you nearly have Rob  :thumbup:

Phil.
Title: Re: Digital oscilloscope project/kit
Post by: krv3000 on December 07, 2015, 05:08:07 PM
brill work rob
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 09, 2015, 05:43:11 PM

Hydro dipping works, you just have to get a good surface finish on the prints (they wet sand well).  Electro plating kits exist but cost a ridiculous amount for what they are.  However it's not rocket science to do in the kitchen when the wife is out   :thumbup:

http://lnx.robotfactory.it/en/copperface-the-new-mini-galvanic-is-coming/

Hi Joules

Electroplating is a walk in the park  :)

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electroless%20Plating/P1040643_zps8l01vaia.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electroless%20Plating/P1040643_zps8l01vaia.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electroless%20Plating/P1040640_zpsvbhb48go.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electroless%20Plating/P1040640_zpsvbhb48go.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Myford%20Index%20attachment/P1040836_zps2f6781da.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Myford%20Index%20attachment/P1040836_zps2f6781da.jpg.html)

Been messing with some Electroless plating

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electroless%20Plating/P1090723_zpsfnukd2dr.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electroless%20Plating/P1090723_zpsfnukd2dr.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electroless%20Plating/P1090733_zpskfae63za.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electroless%20Plating/P1090733_zpskfae63za.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electroless%20Plating/P1090737_zps6i47rwi5.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electroless%20Plating/P1090737_zps6i47rwi5.jpg.html)


All good stuff  :thumbup:.


Here is some copper conductive paint for $40.00

http://www.caswellplating.com/copper-conductive-paint-4oz.html



Hi Tom , thanks for the link  :beer:  , I have a few recipes for conductive paint so I may have ago at brewing my own  :smart:


....... yes it doable with a cnc mill but not everyone has one of those.....................

But you nearly have Rob  :thumbup:

Phil.


 :Doh: so I do Phil  :lol: :lol: I MUST get back onto that project ,,,,,,,,,,,,I MUST i MUST !


brill work rob


Cheers Bob  :beer:



Rob



Title: Re: Digital oscilloscope project/kit
Post by: sparky961 on December 09, 2015, 07:23:47 PM
AHAH!  That's how you get everything so shiny! :P  :zap:

I read through the specs when you first posted about the 'Scope.  Did I understand correctly that the maximum frequency is 20 kHz?  For the price, it still seems a good deal.  Though if I were to get another one to replace the "CRT suitcase" I got rid of a few years back I think I'd want at least a few MHz.  Tempting little tool nonetheless.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 21, 2015, 01:01:37 PM
Hi Sparky

Yes I cheat  :lol:


Well another parcel arrived today ,a component tester . :zap:


(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100738_zpsnns3awmy.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100738_zpsnns3awmy.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100740_zpsygvjsmzg.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100740_zpsygvjsmzg.jpg.html)

I welded all the joints as per instructions .

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100763_zps4d7svnmg.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100763_zps4d7svnmg.jpg.html)


I added the fly leads , Works a charm  :thumbup:

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100762_zpseibjyl9l.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100762_zpseibjyl9l.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100761_zpsfvtuclwt.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100761_zpsfvtuclwt.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100758_zpssclm3565.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100758_zpssclm3565.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100749_zpsavmcnled.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100749_zpsavmcnled.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100746_zpstdv6ylk7.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100746_zpstdv6ylk7.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100745_zpsdgkdjycu.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100745_zpsdgkdjycu.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100744_zpsvotqaadz.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100744_zpsvotqaadz.jpg.html)

There are three pads to test  SMD ,and it has a few other features to explore, not bad for  13  shipped .


Rob
Title: Re: Digital oscilloscope project/kit
Post by: philf on December 21, 2015, 01:52:35 PM
Rob,

That looks very useful. Where did you buy it from?

I nearly sent for an oscilloscope kit like yours the other day. I have two scopes - a small 15MHz very portable one and a 50MHz storage scope (not so portable). I plugged the small one in and up came two beams. 30 seconds later the beams disappeared and there was an awful blown up capacitor smell. Then I got the big one out and no beams to be seen at all. Remove the covers, unmake and make all the internal connectors and voila, it worked.

Cheers.

Phil.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 21, 2015, 02:08:37 PM
Hi Phil

Bummer your scopes going South on you , I have a cracking 100MHz scope Dave BC kindly donated to me , I mainly got the kits for a bit practice and to help understand whats going on , not arsed if I blow the cheap kit one with my prodding and poking about ,I would just build another. 

Here you go  , same place the scope came from  http://www.banggood.com/DIY-M12864-Graphics-Version-Transistor-Tester-Kit-LCR-ESR-PWM-p-986954.html

You can get them off of ebay already built up ,there are a few different flavours to choose from .

Here it is outputting a PWM  :zap:

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100766_zpst18gsa6q.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100766_zpst18gsa6q.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100765_zpsflxb66eq.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100765_zpsflxb66eq.jpg.html)


Cheers Rob
Title: Re: Digital oscilloscope project/kit
Post by: Joules on December 21, 2015, 02:53:31 PM
Useful bit of kit that Rob, and it compliments your scope.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 22, 2015, 10:39:07 AM
Cheers Joules  :beer:


The colour matches my eyes  :lol: 

Rob
Title: Re: Digital oscilloscope project/kit
Post by: raynerd on December 22, 2015, 02:37:57 PM
Rob, thanks for posting this. I believe Father Christmas is bringing me one - well he best had be as I ordered it, collected from the PO and gave it to my wife  :thumbup:

I`ve been looking at a decent signal gen. as I have nothing to use it with at home! they do some kits for 20 and nearly got one last week but the kids have soaked up all my cash this month!

Cheers again Rob

Chris
Title: Re: Digital oscilloscope project/kit
Post by: Joules on December 22, 2015, 02:45:51 PM
Use your sound card, on PC, tablet etc.  Some good waveform generators, ok so your limited to 20khz or maybe 48khz if your really lucky.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 22, 2015, 02:53:17 PM
Nice one Chris  :thumbup:

Is it the bangood Signal gen kit  ?  http://www.banggood.com/DDS-Function-Signal-Generator-Module-DIY-Kit-Pulse-Sine-Wave-p-958215.html I have one on it way .


And a power supply kit        http://www.banggood.com/0-30V-2mA-3A-Adjustable-DC-Regulated-Power-Supply-DIY-Kit-p-958308.html  :zap:


I must have about ten wee electronics kits to build ,I bought about 5  PIC projects kits from Rapid Electronics .


Rob
Title: Re: Digital oscilloscope project/kit
Post by: shipto on December 22, 2015, 05:00:14 PM
Mr Wilson please stop I only have 4 kids and my birthday isnt until June so will have to start buying myself if you keep posting these links  :lol:
Title: Re: Digital oscilloscope project/kit
Post by: raynerd on December 23, 2015, 02:12:02 AM
Yes, Rob, that's the one.

I've also been considering building one of my own around a pic or arduino. There are a lot of plans online.
Title: Re: Digital oscilloscope project/kit
Post by: philf on December 23, 2015, 04:12:08 PM
Hi Phil

Bummer your scopes going South on you , I have a cracking 100MHz scope Dave BC kindly donated to me , I mainly got the kits for a bit practice and to help understand whats going on , not arsed if I blow the cheap kit one with my prodding and poking about ,I would just build another. 

Here you go  , same place the scope came from  http://www.banggood.com/DIY-M12864-Graphics-Version-Transistor-Tester-Kit-LCR-ESR-PWM-p-986954.html


Cheers Rob

Thanks Rob,

I spent hours looking at all the goodies available from Banggood.

I've ordered a little LCD Touch Screen for my Raspberry PI for just over 8. I'm thinking it's best to order only one thing at a time to keep the total cost below the 15 value when you may or may not be billed for VAT (and the 8 + VAT fee for collecting the VAT). (Or do they put fictitious values on the packages?)

Luckily I got both my scopes running again. I found an identical capacitor on eBay for just over 1 delivered. A couple of 20mm 125mA slow blow fuses cost more. I'm OK for a sine/square/sin wave generator 0.1Hz to 2MHz but yours takes a lot less space and tells you what it's doing.

Are you going to tell us what other kits you bought or do we have to wait?

Cheers.

Phil.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 24, 2015, 03:50:43 AM
Mr Wilson please stop I only have 4 kids and my birthday isnt until June so will have to start buying myself if you keep posting these links  :lol:

Or you could get busy and knock out a few more kids  :lol:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 24, 2015, 03:59:23 AM
Yes, Rob, that's the one.

I've also been considering building one of my own around a pic or arduino. There are a lot of plans online.

Interesting Chris ,

Do  you have any links handy , no worries if you dont I could have a look over the holidays . I have PICAXE , GENIE and Arduino ,,,,,,,,,,,,,,,,to mess with .


I must say for the money the Bangood kits I have receved have all worked , the PCB's are cracking quality (well to my inexperienced eyes they are ) ,  no parts missing  , probably not the best components but for the few quid they cost I am happy .


Rob
Title: Re: Digital oscilloscope project/kit
Post by: shipto on December 24, 2015, 04:11:57 AM
Mr Wilson please stop I only have 4 kids and my birthday isnt until June so will have to start buying myself if you keep posting these links  :lol:

Or you could get busy and knock out a few more kids  :lol:


Rob
Discussed it with wife and she threatened all sorts of nasty things to my bits  :zap:  :lol:
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 24, 2015, 04:21:43 AM

Thanks Rob,

I spent hours looking at all the goodies available from Banggood.

I've ordered a little LCD Touch Screen for my Raspberry PI for just over 8.

Luckily I got both my scopes running again. I found an identical capacitor on eBay for just over 1 delivered. A couple of 20mm 125mA slow blow fuses cost more. I'm OK for a sine/square/sin wave generator 0.1Hz to 2MHz but yours takes a lot less space and tells you what it's doing.


Cheers.

Phil.


Hi Phil ,

I am pleased yoy have your scopes up and running  :thumbup:  , what are you making with a Raspberry pie and touch screen ?   


Quote
I'm thinking it's best to order only one thing at a time to keep the total cost below the 15 value when you may or may not be billed for VAT (and the 8 + VAT fee for collecting the VAT). (Or do they put fictitious values on the packages?)


They post everything separately , well all of my orders have come split so far  and I dont think they can read Chinese at the sorting office  :med: 




Quote
Are you going to tell us what other kits you bought or do we have to wait?


Classified Phil all very hush hush , mums the word  :lol: 


OK! , A real mixed bag , the kits above  scope ,component tester ,power supply , signal generator  . Then there is the programmable stuff , PICAXE ,GENIE and Arduino projects and development boards all very basic . some 555 projects , times that sort of stuff , a DC PWM motor controller .   

All in an aid to get to grips with electronics lark , I must admit its fun messing with these kits  :zap:


Rob 


Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 24, 2015, 04:22:34 AM
Mr Wilson please stop I only have 4 kids and my birthday isnt until June so will have to start buying myself if you keep posting these links  :lol:

Or you could get busy and knock out a few more kids  :lol:


Rob
Discussed it with wife and she threatened all sorts of nasty things to my bits  :zap:  :lol:


 :lol: :lol: :lol: :lol: :lol: spoil sport  :lol:



Rob
Title: Re: Digital oscilloscope project/kit
Post by: philf on December 24, 2015, 08:04:13 AM

I am pleased you have your scopes up and running  :thumbup:  , what are you making with a Raspberry pie and touch screen ?   


Hi Rob,

I'm using the Raspberry Pi for our Hydro Scheme.

You may regret asking me what I'm doing with it but here goes:

We currently have two grease pumps which supply biodegradeable grease to the bottom bearings of the Archimedes screws. Each top bearing has two Simalube grease cartdridges. These have a dry cell which generates hydrogen to pressurise the cartridge thus forcing the grease out into the bearing. These cartridges are expensive and cost around 250/year all to dispense around 5 worth of grease. I've ordered an SSVD which is a valve which will send a certain proportion of the grease pump output to each of the 6 grease points. I need 10gm of grease/day to each of the two bottom (submerged) bearings and 1gm/day to each of the ports on the top bearings. The SSVD has an indicator pin which moves in and out as grease moves through it. I'm detecting this movement with a proximity sensor. This connects to the Pi through an opto-isolator to keep 24v well away from the inputs of the Pi.

The grease pump will be set to run for approx 20 seconds every 40 minutes. When the Pi sees the pin move it will start timing. If it doesn't see the pin again within say 41 minutes it will sound an alarm in our power house and, more importantly as the power house is normally unmanned, send an email telling a few of us that the grease pump may be empty or may be faulty. This was my first venture into the world of Python programming.

Flushed with the success of this I set about trying to measure screw speed.

The system records screw speed but only once every 15 minutes. We think we've had some violent overspeeds but these have been missed by the log file. 6 tons of not well balanced screw spinning fast could have disastrous consequences.  The screws normally run very slowly (max of about 30 rpm,  min about 6 rpm) so I thought the Pi would have no problems looking at a proximity sensor which is set to detect big socket screw heads on a coupling between the screw and the gearbox. There are 12 bolts on the coupling so the max frequency I'd be looking at would be 6Hz. Not rocket speeds. I decide that the best way to get the speed would be just to get the time between the sensor seeing two bolt heads.

I soon found that, even at the pedestrian speeds I was looking at, the Pi is useless at real time stuff when using a multitasking operating system unless you use interrupts. This is where it got scary for me.

For GPIO control I was using pigpio which had a function something like wait_for_edge.fallingedge with timeout which I thought would work nicely and the timeout function would cope with a screw being stopped. The results I got were fairly promising but every now and then a spurious result. This is when I got the scopes out to look at the output from my pulse generator (which I was using to simulate the output I'd get from a running screw) as I thought it may be inconsistent - it wasn't.

I contacted the author of pigpio and emailed him my code. He very quickly replied telling me that the times returned by his wait_for_edge function could be up to 0.1sec out! He would change his documentation to make this clear. He suggested using callbacks (from interrupts) and within a couple of hours had emailed me some basic working code.

I then set about filtering the results to only show > 1% changes in speed and writing the results to a log file with a timestamp. Without the filter the files would grow to enormous proportions. I'm just getting the code right for starting a new log file at 00:00:00 every day and emailing myself the previous day's file.

The touch screen is so I can have a live screw speed display in the power house. Then I might think about drawing speed/time graphs.

You did ask!  :lol:

Have a Very Good Christmas and a Happy & Healthy 2016.

 :beer:

Phil.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 24, 2015, 08:52:07 AM
Hi Phil   :palm:


You lost me at " Hi Rob "   :lol: :lol: :lol: only joking mate .


Arh I keep forgetting your Hydro project  ,great stuff . Two real world applications for a small microprocessor very interesting , all way above my pay grade at the moment , I am at the make LED blink stage  lol  :palm: ,That will be one hell of a saving on the grease bill ,money that could be better spent elsewhere on the project .

 I was hoping to build/come up with something similar . I want to log when and for how long a battery has been on charge .  :scratch: 

All the best to you and yours Phil  :beer: 

Rob

PS you full recovered from your cycling mishap ? 

 
Title: Re: Digital oscilloscope project/kit
Post by: philf on December 24, 2015, 10:55:34 AM
Hi Rob,

3 weeks ago the only python I knew of was something that squashed and ate you in a nightmare!

I too was pleased when I got an LED to flash for the first time.

I wrote tons of stuff in BBC Basic but a long time ago. I don't think that knowing Basic helps at all with Python.

If you look for online documentation you have to be very careful that your looking at the documentation for the version of Python you're using as things can change dramatically between versions.

Timing things looks fairly simple when you see that datetime.now() returns something like 24/12/2015 15:06:44.995179 which is accurate to the microsecond. However as I found out actually getting microsecond timing of events needs interrupts. If you only need a time to the odd second or so it should be straightforward.

My latest cycling mishap did for my shoulder. It's very slowly getting better. I just have to remember not to try to lift anything heavy above shoulder height.

I've just been planing 0.5mm off the top of the front door. We've just had the hall, landing and two lots of stairs plastered - everything's damp and the door had swollen. Hopefully we should be dry when the family come round for tea tomorrow.

I've got the Pi, Function Generator, Pulse Generator on the floor in the living room with wires trailing between. I'd better put them away before tomorrow or else I'll get some grief! I started with a mouse and monitor connected as well but now I've installed VNC and can drive it all from my laptop.

Cheers.

Phil.

Title: Re: Digital oscilloscope project/kit
Post by: raynerd on December 24, 2015, 03:06:37 PM
Hi Rob, loads of shields and projects about - like you said googling brings up a lot. I'm guessing that a simple square wave will be made with a simple pin going high and low - either on an interrupt or delayed loop. Dead simple, pin1 go high, delay, pin1 go low, delay and loop. I can see from the online projects that there is more to getting nicer wave forms. I've got s few play stepper motor drivers so I'll be giving them a test to get my scope going. Rob, have you looked at the Mikroelectronica stuff? - their easyPic 6 board got me flying with some proper pic coding in C. Well worth a look at if you have some spare cash and admittedly it isn't the cheapest.


Phil, just wanted to say hello and merry Christmas. I was in touch with you weekly for many months then dropped off the face of the Earth when I moved house a year ago. Hope all is well.
Title: Re: Digital oscilloscope project/kit
Post by: philf on December 24, 2015, 05:01:07 PM

Phil, just wanted to say hello and merry Christmas. I was in touch with you weekly for many months then dropped off the face of the Earth when I moved house a year ago. Hope all is well.

Hi Chris,

Hello and a Merry Christmas to you.

You'd see a difference in our hall now now it's plastered. I've earned some Brownie points by getting this done.

I might replace some of my equipment with stuff from BangGood - it would take up a lot less space.

(http://listerengine.com/coppermine/albums/userpics/10017/P1050018_zpswdg2b5a3.jpg)

It's all got to disappear later!

Cheers.

Phil.
Title: Re: Digital oscilloscope project/kit
Post by: sparky961 on December 24, 2015, 05:55:16 PM
Eeek... watch out for static electricity with all that carpet under foot!

 :zap:
Title: Re: Digital oscilloscope project/kit
Post by: philf on December 24, 2015, 06:03:49 PM
Eeek... watch out for static electricity with all that carpet under foot!

With the humidity level in the house since the plastering static isn't an issue.  :thumbup:
 
Phil.
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on December 25, 2015, 06:08:37 AM
Hi Rob
I treated myself to the oscilloscope kit for xmas, I think I may have bitten off a bit more than I can chew tho, my kit hasn't got the smd's presoldered  :Doh:
I was wondering, can I run this from a 9volt battery or does it need a proper power supply?
I also ordered the component tester and comes with a battery connector so thats ok, mind you, I haven't received that yet.

cheers and have a good holiday.
Roy.
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on December 25, 2015, 06:22:22 AM
Roy,
The scope needs a 9.0v supply.....
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 25, 2015, 07:29:51 AM
Hi Rob
I treated myself to the oscilloscope kit for xmas, I think I may have bitten off a bit more than I can chew tho, my kit hasn't got the smd's presoldered  :Doh:
I was wondering, can I run this from a 9volt battery or does it need a proper power supply?
I also ordered the component tester and comes with a battery connector so thats ok, mind you, I haven't received that yet.

cheers and have a good holiday.
Roy.

Hi Roy

There are a few videos on you tube on SMD soldering ,it was pot luck what I got .

Works a charm on a 9V battery

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100769_zpsupvrol7f.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100769_zpsupvrol7f.jpg.html)


Only draws 109 milli amps , you could omit the white connector to the right of the power socket and solder a 9v battery snap connector to there . or I could send you the plug that fits the white connector when they arrive ,I ordered 10 ,you're more than  welcome to one . 



All the best ,Rob 

Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 25, 2015, 07:35:56 AM
. Rob, have you looked at the Mikroelectronica stuff? - their easyPic 6 board got me flying with some proper pic coding in C. Well worth a look at if you have some spare cash and admittedly it isn't the cheapest.




Hi Chris

I was just looking  at that very  board last week ,I was thinking I  may order one in the new year , so you reckon they are  good value  ?  what are  the training manuals like ?   


All the best ,Rob




Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on December 25, 2015, 07:47:15 AM
Thanks for the Info Rob. I've been watching Dave Jones on the EEV blog https://www.youtube.com/user/EEVblog/videos and he has a tutorial on smd soldering.

Thamks for the offer of a plug, it looks like a standard computer type connector, I'll look through my collection of junk trash useful bits and get back to you.

cheers

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 25, 2015, 07:47:56 AM

(http://i1058.photobucket.com/albums/t415/paf51/P1050018_zpswdg2b5a3.jpg)

It's all got to disappear later!

Cheers.

Phil.

Hi Phil


I reckon the  bango gear is no where near as good as your pro kit . Looks like built your own board too ,is that a signal generator your using for testing ?



All the best ,



Rob
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 25, 2015, 07:54:37 AM
Thanks for the Info Rob. I've been watching Dave Jones on the EEV blog https://www.youtube.com/user/EEVblog/videos and he has a tutorial on smd soldering.

Thamks for the offer of a plug, it looks like a standard computer type connector, I'll look through my collection of junk trash useful bits and get back to you.

cheers

Roy.

Hi Roy


Have a look at this video ,it the kit you will receive .


 
 



Cheers Rob


Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on December 25, 2015, 09:25:22 AM
Best way I find for smd stuff is to use solder paste, applied with a cocktail stick,rather than conventional solder......a small tipped iron is essential to avoid overheating the components...
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on December 25, 2015, 02:55:36 PM
Hi again.
I just ordered one of these http://www.ebay.co.uk/itm/SMT-SMD-Component-Welding-Practice-PCB-Board-Soldering-DIY-Kits-I1-/181941791530?hash=item2a5c936b2a:g:ZQcAAOSwcBhWVSo3

I thought I should get some practice in before I attempt the kits.

you can't go wrong at this price.

I love the way all these places call it "welding", think I should get the welder out, what do you reckon 80 amps? :zap: :zap: :zap:

cheers

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: raynerd on December 26, 2015, 07:26:16 PM
. Rob, have you looked at the Mikroelectronica stuff? - their easyPic 6 board got me flying with some proper pic coding in C. Well worth a look at if you have some spare cash and admittedly it isn't the cheapest.




Hi Chris

I was just looking  at that very  board last week ,I was thinking I  may order one in the new year , so you reckon they are  good value  ?  what are  the training manuals like ?   


All the best ,Rob

Hi Rob, slow reply it's been a busy few days. My house is fine but we have had flooding today so been out helping and taking random videos. The local old vacant pub collapsed into the river and I took a video of that that made the BBC news. Then got a call to say grandparents house was flooding so ran to there.... None stop.

Anyway, I posted this video in 2010.'im sure there is a new board now but I expect the principle to be the same. Board and manual are fantastic but hardcore... It isn't for the faint hearted but basically it is real programming and the board has everything you want on it. I used to for a lot of fun projects but I also built a power feed stepper motor controlled for my old milling machine with it.

I'm absolutely no expert and I'm sure others will chime in and correct me but to me, the biggest thing is that it is a true development board. It has EVERYTHING on it you can think of, already wired up, you just select it and code it. It is expensive in that I also used their compiler and programming suit, MikroC : http://www.mikroe.com/mikroc/pic/.   I THINK you have no option but to use their software as well but I could be wrong. There are hundreds of demo code and I often copied a demo code and worked my own code from this, it May be worth taking a look around see if you can get the software at a reasonable price before you buy the board. Again, it's coding in C and you have to setup the Pic where as that has been done for you with arduino. It is harder to use but I enjoyed it. Another thing I found is that arduino is so cheap that you'd code it, and then I'd literally use the arduino inside the project itself. So like the penny pusher I made my daughter had two arduino in there, as part of the machine. Of course  with the easyPic Deb board, you practice and develop on the board and then programme the PIC and then have to make your own circuit for the chip from scratch for your device. Again, more to it but I found it rewarding. It's all a lot more involved than the arduino stuff.

This is the review/video of did of the easyPic 6 back 5 years ago in 2010:



 


Title: Re: Digital oscilloscope project/kit
Post by: RussellT on December 27, 2015, 05:53:50 AM
 The software is quite expensive if you want the full version, but the free version gives you quite a lot of scope - it has a limit on the size of the program.  It's also available in different flavours, C, basic and pascal.

Russell

Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 28, 2015, 07:40:03 AM
Hi again.
I just ordered one of these http://www.ebay.co.uk/itm/SMT-SMD-Component-Welding-Practice-PCB-Board-Soldering-DIY-Kits-I1-/181941791530?hash=item2a5c936b2a:g:ZQcAAOSwcBhWVSo3

I thought I should get some practice in before I attempt the kits.

you can't go wrong at this price.

I love the way all these places call it "welding", think I should get the welder out, what do you reckon 80 amps? :zap: :zap: :zap:

cheers

Roy.


Hi Roy


Wize move getting a wee bit of practice in before moving onto the real project , I noticed Banggood do those practice SMD boards , I may send off for some practice boards to .


Are you going to get an SMD rework station ?    those cheap ones seam popular .


What so I dont TIG the components to the board  :lol: :lol:


Cheers Rob
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 28, 2015, 07:50:21 AM
. Rob, have you looked at the Mikroelectronica stuff? - their easyPic 6 board got me flying with some proper pic coding in C. Well worth a look at if you have some spare cash and admittedly it isn't the cheapest.




Hi Chris

I was just looking  at that very  board last week ,I was thinking I  may order one in the new year , so you reckon they are  good value  ?  what are  the training manuals like ?   


All the best ,Rob

Hi Rob, slow reply it's been a busy few days. My house is fine but we have had flooding today so been out helping and taking random videos. The local old vacant pub collapsed into the river and I took a video of that that made the BBC news. Then got a call to say grandparents house was flooding so ran to there.... None stop.

Anyway, I posted this video in 2010.'im sure there is a new board now but I expect the principle to be the same. Board and manual are fantastic but hardcore... It isn't for the faint hearted but basically it is real programming and the board has everything you want on it. I used to for a lot of fun projects but I also built a power feed stepper motor controlled for my old milling machine with it.

I'm absolutely no expert and I'm sure others will chime in and correct me but to me, the biggest thing is that it is a true development board. It has EVERYTHING on it you can think of, already wired up, you just select it and code it. It is expensive in that I also used their compiler and programming suit, MikroC : http://www.mikroe.com/mikroc/pic/.   I THINK you have no option but to use their software as well but I could be wrong. There are hundreds of demo code and I often copied a demo code and worked my own code from this, it May be worth taking a look around see if you can get the software at a reasonable price before you buy the board. Again, it's coding in C and you have to setup the Pic where as that has been done for you with arduino. It is harder to use but I enjoyed it. Another thing I found is that arduino is so cheap that you'd code it, and then I'd literally use the arduino inside the project itself. So like the penny pusher I made my daughter had two arduino in there, as part of the machine. Of course  with the easyPic Deb board, you practice and develop on the board and then programme the PIC and then have to make your own circuit for the chip from scratch for your device. Again, more to it but I found it rewarding. It's all a lot more involved than the arduino stuff.

This is the review/video of did of the easyPic 6 back 5 years ago in 2010:






Hi Chris

So pleased to hear your safe from the flooding , York is a real mess .

Yes the new board is the EasyPIVv7   , looks a bit different to your board . As you say they cover most bases with whats on the board and the plugin modules .


There are just so many options to go at nowadays ,Arduino, Raspberry Pi , PIC  etc   and everything seams to use a different language .  :palm:



Cheers Rob   
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 28, 2015, 07:53:01 AM
The software is quite expensive if you want the full version, but the free version gives you quite a lot of scope - it has a limit on the size of the program.  It's also available in different flavours, C, basic and pascal.

Russell


Hi Russell

Cheers for the input , more to think about . decisions decisions .




Rob 
Title: Re: Digital oscilloscope project/kit
Post by: PekkaNF on December 28, 2015, 07:58:19 AM
.....
So pleased to hear your safe from the flooding , York is a real mess .
....

We have been watching few days the news, that rain/flood looks pretty bad. They interviewed some people and I was impressed in how well people seem to take such a natural disastre.

Pekka
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on December 28, 2015, 09:32:40 AM
( snip)


Hi Roy


Wize move getting a wee bit of practice in before moving onto the real project , I noticed Banggood do those practice SMD boards , I may send off for some practice boards to .


Are you going to get an SMD rework station ?    those cheap ones seam popular .

I already have a hot air paint stripper, will that do. :D :D :D :D


What so I dont TIG the components to the board  :lol: :lol:

I only have a stick welder so perhaps I should dial the current down a bit. :) :) :)


Cheers Rob
[/quote]


Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 28, 2015, 11:11:07 AM
 :lol: :lol:  :thumbup:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on December 29, 2015, 06:21:56 AM
Hi Rob,
I just received another kit for xmas, the component tester.
I must be a sucker for punishment  :bang:

I must say, the assembly instructions are underwhelming to say the least.
most of it seems clear enough, did you have any problems assembling yours?


cheers

Roy.

EDIT.

I just found an online pdf instruction sheet, it's in chinglish but meh.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on December 29, 2015, 11:21:41 AM

I must say, the assembly instructions are underwhelming to say the least.
most of it seems clear enough, did you have any problems assembling yours?


cheers

Roy.


Make sure you use a big enough iron with a decent tip but dont overheat the components...... :lol:
Title: Re: Digital oscilloscope project/kit
Post by: Joules on December 29, 2015, 11:36:45 AM
Still not enough, for these bloody heatsinks...
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 29, 2015, 01:00:55 PM
Hi Rob,
I just received another kit for xmas, the component tester.
I must be a sucker for punishment  :bang:

I must say, the assembly instructions are underwhelming to say the least.
most of it seems clear enough, did you have any problems assembling yours?


cheers

Roy.

EDIT.

I just found an online pdf instruction sheet, it's in chinglish but meh.

Roy.

Hi Roy


 :lol: :lol: :lol: aye there not the best instructions , mine went together with only two problems   :zap:   , first was a faulty battery lead ,so I had to replace that , and the second was down to me

not being able to find the on/off switch  :palm:  ,,,,,,,,,,,,,,,,,,,,,,,,,, you have to press the rotary encoder  :bang:


My function generator kit arrived today ,,,,,,,,,,,,,,,,,,,,,,, it needs a +12 -12 and 5v power supply to run it  :zap:


Cheers Rob


PS John ,Joules I  have some 6.3mm carbon arc rods    :lol:





 
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on December 29, 2015, 01:32:44 PM

I must say, the assembly instructions are underwhelming to say the least.
most of it seems clear enough, did you have any problems assembling yours?


cheers

Roy.


Make sure you use a big enough iron with a decent tip but dont overheat the components...... :lol:

no worries there I have a soldering station that goes from 200 to 480 C with a selection of tips. also some 0.46 dia solder.

Roy,
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on December 29, 2015, 01:48:08 PM
Hi Rob
which kit did you get, it sounds a bit fussy needing various voltages.
do you have a power supply in mind?  I know computer power supplies give +12 and +5, I don't know about -12 tho.

thanks for the heads up on the battery connector, I'll test mine first, I've ordered the case for it as well but it hasn't arrived yet.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 29, 2015, 02:13:08 PM
Hi Rob
which kit did you get, it sounds a bit fussy needing various voltages.
do you have a power supply in mind?  I know computer power supplies give +12 and +5, I don't know about -12 tho.

thanks for the heads up on the battery connector, I'll test mine first, I've ordered the case for it as well but it hasn't arrived yet.

Roy.


Hi Roy

Cheers for tip about  the computer power supply  :thumbup:

You going all up market on us and getting the case   :clap: :clap:


There is a wee circuit diagram for a power supply in the instructions , so now I have the fun of learning about voltage regulators and the likes , just another project  :zap:


Maybe I should  take more notice of what I am actually purchasing , ,,,,,,,,,,,narh I like the letter box Russian roulette      :lol:



Rob

PS   Cheers for the  tip about  the computer power supply  :thumbup:
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on December 29, 2015, 02:48:27 PM
Many of the older style at power supplies had -12v for the genuine serial rs232 ports..... If you come across summat that might be useful, check the label on it...

I think modern day psus dont cater because of usb.......

 A suitable supply can be made from a 9v ac transformer, 2 diodes, a couple or three capacitors and a 7805 regulator.....for starters...

Shout up if any help needed... :zap: I'll try and find someone who knows about this stuff... :lol: :lol:
Title: Re: Digital oscilloscope project/kit
Post by: kayzed1 on December 29, 2015, 02:51:42 PM
PC psu

https://www.google.co.uk/imgres?imgurl=http://cdn.makezine.com/uploads/2014/04/da87333a_atx24-1bcq.jpg&imgrefurl=http://makezine.com/projects/computer-power-supply-to-bench-power-supply-adapter/&h=1200&w=2132&tbnid=RxJlE_7aG5jGQM:&tbnh=131&tbnw=232&docid=fxYEqitmph33xM&usg=__3jHSveXxfrOggSn7kVdzrFYBUmc=&sa=X&ved=0ahUKEwjX976x64HKAhUEXRoKHUjiBasQ9QEIIzAA
Title: Re: Digital oscilloscope project/kit
Post by: kayzed1 on December 29, 2015, 02:53:51 PM
I think i have a spare 300w unit in the shed Rob. Ow! and an adapter to link to it to give the screw conector thingy's. I made a couple for mates a while back.
Lyn.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 29, 2015, 03:21:55 PM
Cheers For the offer Lyn  :beer: I may take you up on it   :thumbup:


Thanks for the link to ,interesting and helpful . I think you can now get a breakout board for computer PSU's


I have attached the PSU  circuit drawing ( re done by my very own hand )  that came with the function generator .


Cheers Rob


EDIT  corrected PSU circuit diagram 
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 29, 2015, 03:30:48 PM
they do https://proto-pic.co.uk/atx-breakout-board-bench-power-supply/?gclid=Cj0KEQiA-4i0BRCaudDcrrnDi6kBEiQAZSh5f7HacIirg9OqGRTUPSx2NtcgnfsOxdP_Gq7kYD7R62UaAuMK8P8HAQ

and ebay

http://www.ebay.co.uk/itm/24Pins-ATX-Benchtop-Power-Board-Computer-Power-Supply-Breakout-Adapter-/181964686234?hash=item2a5df0c39a:g:C5IAAOSwk1JWcpK2


Rob
Title: Re: Digital oscilloscope project/kit
Post by: kayzed1 on December 29, 2015, 04:47:22 PM
Tis the second board io have on these, if you want it PM me your address...
Lyn.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 30, 2015, 12:17:12 PM
The Signal generator project arrived from Banggood yesterday , so I welded all the bits together today  :zap:


(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100775_zpslupqngow.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100775_zpslupqngow.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100776_zpsiizlugbd.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100776_zpsiizlugbd.jpg.html)


Cant test it until I build a power supply for it  :coffee: , also the PSU circuit diagram I posted earlier has a couple of faults  :Doh:


#1   the supply needs to be more like +18 - 18 volts   as a 12 regulator needs more than 12 volts

#2  the  -12 rail needs a 7912 voltage regulator not a 7812  ,the  7912 is a -12v  reg   .


Cheers Rob   
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 30, 2015, 12:33:21 PM
Going to cobble together something like this  :zap: :zap:

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/Circuit%20Wizard%20-%20Power%20Supply_zpsxzpyjuet.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/Circuit%20Wizard%20-%20Power%20Supply_zpsxzpyjuet.jpg.html)


Rob  :coffee:
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on December 30, 2015, 12:43:57 PM
Rob,
Nicely assembled...  :clap:   Looks pretty neat and tidy....Hope it works for you..... :zap:


Just be aware that the pin outs for 78 and 79 v regs are different.......
The + 12v reg may need a heatsink on it too as its supplying  current for the 9 & 5 v regs....
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 30, 2015, 01:03:24 PM
Rob,
Nicely assembled...  :clap:   Looks pretty neat and tidy....Hope it works for you..... :zap:


Just be aware that the pin outs for 78 and 79 v regs are different.......
The + 12v reg may need a heatsink on it too as its supplying  current for the 9 & 5 v regs....

Cheers John , if you see the northern lights tis just me going up in smoke  :lol:


The reg pinout got me on the simulation ,,,,,,,,,,was wondering why I was getting -18v  when it should have been -12 v ,,,,,,,,,,,,,,had the 7912 wired wrong  :palm:


I have ordered heatsinks for all the regs  :thumbup:


anything else you or anyone could recommend to improve things   ?    :wave:



Cheers Rob
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on December 30, 2015, 02:28:02 PM
You've no business wiring up 79xx regulators arseaboutface, that's my favourite faff-up.  :D

BTW, you should really put a 100nF to ground close to the o/p pins on 78xx and 79xx ( and any other regulator for that matter ) otherwise they will tend to oscillate ..  :thumbup:

Happy New Year 2U and Mrs. Rob ...  :wave:

Dave
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 30, 2015, 04:32:40 PM
 :lol: :lol: Hi Dave I bet it will not be the last time I get a component arse about face  :Doh:




I will amend the circuit tomorrow as you suggest  :thumbup:  , I was wondering why I had a strange ripple  on the 9 volts out .

All the best to you Dave  :beer:  :ddb: :beer:

Cheers  Rob
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on December 30, 2015, 04:57:43 PM
Hi Rob

Cheers  :beer: 

First time I had that nonsense was years ago, making a 1MHz Colpitts Oscillator. The circuit was driven by a 7809 and it ekkled quite handsomely at 1.6MHz. No way could I get the damn thing to work properly. Eventually discovered it was the pox-etten 9V with a hideous 1.6MHz ripple  ..  :doh:

Back in my analogue days ... long ago ...

Dave

Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 31, 2015, 06:32:53 AM
Something like this Dave  :wave:


(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/Circuit%20Wizard%20-%20Power%20Supply_zps6bbyasg5.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/Circuit%20Wizard%20-%20Power%20Supply_zps6bbyasg5.jpg.html)

I think I will change the output connector to -12, 0 , +5 ,+9, +12 


cheers Rob  :beer:
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on December 31, 2015, 09:38:45 AM
Well, 100uF would maybe improve things, but ..... it's the high frequency instability which causes the grief. So, if you actually freakin' READ like what I have writted  100 nF ie. 0.1 uF ...   :D  :D

Electrolytics in general are not very good at getting shot of HF noise 'cos of their inherent construction. An el-cheapo ceramic is all you need. You can leave the 100uF caps. there. Won't harm anything.

Good day to you, Sir ...  :ddb:    Late lunch today ... starving ....

BTW
I think your 0V centre-tap should be grounded ??

And that is the symbol for a safety earth, ground is an inverted triangle.  :thumbup:

What current are you drawing from these regulators anyway? The 12V ic's. will have some 25V i/p, this gives about 13V dropped across them. If I assume the max. of 1A they will dissipate some 13W which is a lot for a TO220 package without a fairly large heat-sink and/or a fan. A 15 - 0 - 15 transformer would be a bit better ...

Dave

Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 31, 2015, 10:09:22 AM
 :lol: :lol: :lol: :lol: I was full of the party spirits when I redrew it last night  Dave ,,,,,,,,,,,,,you try reading with a pint and a half of vodka and coke in you  :lol: :lol:  :beer:


Cheers Rob , could do with some bait myself .
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 31, 2015, 10:28:24 AM

BTW
I think your 0V centre-tap should be grounded ??

And that is the symbol for a safety earth, ground is an inverted triangle.  :thumbup:

What current are you drawing from these regulators anyway? The 12V ic's. will have some 25V i/p, this gives about 13V dropped across them. If I assume the max. of 1A they will dissipate some 13W which is a lot for a TO220 package without a fairly large heat-sink and/or a fan. A 15 - 0 - 15 transformer would be a bit better ...

Dave


oops I thought there was something else missing ,its grounded  :zap: ,, about 200 milli amps Dave

Have a butchers at the new new version PDF  :lol:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on December 31, 2015, 10:29:11 AM
Well, my thoughts are:


The fuse is in the wrong position ......transformer primary would be better......
Not sure if there's sufficient headroom for the 9.0 v reg to work properly.....3.0v differential between in and out....close to the drop out voltage.....

If I were designing it, I'd be looking for around 16.0v in to the 12.0v reg, then connect the 9.0v to the 16.0 v supply....

A 15-0-15 transformer would be better as Dave says....I'd even try going as low as 12-0-12 to reduce the dissipation even further.....

Item 311 512 from   https://www.esr.co.uk/electronics/products/frame_transformers.htm
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 31, 2015, 10:55:31 AM
Well, my thoughts are:


The fuse is in the wrong position ......transformer primary would be better......
Not sure if there's sufficient headroom for the 9.0 v reg to work properly.....3.0v differential between in and out....close to the drop out voltage.....

If I were designing it, I'd be looking for around 16.0v in to the 12.0v reg, then connect the 9.0v to the 16.0 v supply....

A 15-0-15 transformer would be better as Dave says....I'd even try going as low as 12-0-12 to reduce the dissipation even further.....

Item 311 512 from   https://www.esr.co.uk/electronics/products/frame_transformers.htm

Cheers John

I will move the fuse , I should have had a question mark next to it .

I have at hand a 12-0-12 and a 18-0 -18 transformer  , the simulation did not like the 12-0-12 transformed ,no head room , and the simulator says I should get 9.74v  :scratch:

See new new new attachment lol


Cheers for the input lads  :thumbup:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on December 31, 2015, 11:15:18 AM
John is right, it will work with a 12 0 12 transformer .... depends somewhat on the VA rating ...  :thumbup: so what is the rating on the one you have ??

Why ??

OK. So, lets imagine we have a tranny 12 0 12 out at 24VA [for no other reason that it's easy to work out]  :thumbup:

24vac out 24VA gives 1 amp load current.

BUT  ... trannies here assume the EU nominal volts in to be 230vac  ... we're often nearer 245vac.

The output voltage is at the full rated load ! ie. 1 amp.

Now we come to LOAD REGULATION

On a relatively small tranny it won't be very good, at 24 VA it's probably about 12%.

Which means at no load the output volts will be 12% higher than the full load 24 vac ie. some 26 vac.

To compound the felony we are shoving more volts into it than the 230vac nominal.

The upshot of this tripe means we will get considerably more DC volts, AT SMALL LOADS, than we think.

Hence a 12 0 12 12VA tranny will be quite OK in practice even if your wretched simulator doesn't think so.

If you get one of these really titchy 3VA trannies and measure the no-load volts out you will be surprised [ at first anyway] they are often way above the advertised value  :zap:  but shove a 50mA load on them and they calm down.


Dave

Somewhere I have the schematic for one I built, see if I can find it  ... might be on the laptop ...  :scratch:

Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on December 31, 2015, 11:17:49 AM
There are a couple of reasons for putting the fuse in the pri,
1) it will blow if theres a short on the secondary or primary side......

2) the big 2200mfd cap will appear as a short circuit for a brief period as it charges up....depending on the fuse size, would cause it to blow...
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 31, 2015, 11:27:24 AM


Hence a 12 0 12 12VA tranny will be quite OK in practice even if your wretched simulator doesn't think so.



Dave




Whats the poor thing done to you  :lol: :lol: I will try both .

The  transformers I have are 3VA



There are a couple of reasons for putting the fuse in the pri,
1) it will blow if theres a short on the secondary or primary side......

2) the big 2200mfd cap will appear as a short circuit for a brief period as it charges up....depending on the fuse size, would cause it to blow...


Its moved John  :thumbup:



Rob
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on December 31, 2015, 11:40:47 AM
I've not been a big fan of sims.....much prefer to see what happens if approach.....

Best thing to do Rob, is lash up the circuit on some Vero board with the 12 v transformer and measure what comes out.....

If the usual approach of  V ac in x 1.414 is applied and subtract the Vdrop for the diodes, the actual output is usually different to the theoretical calculated..... :coffee:

The meter never lies.... :lol:
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 31, 2015, 11:44:16 AM
I have attached two files showing the regulator output voltages , one with an input of 12-0-12  and the other 18-0-18

The 12-0-12 gives out less than 12 volts  :scratch:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on December 31, 2015, 12:17:35 PM
3VA ???  :bugeye:  Like running 'em lean 'n mean eh ?  :D
Don't forget to phone up National Grid PLC before you power up. Tell 'em to brace themselves ...  :lol:  :lol:

Found the schematic:

The bottom bit, ie. + / - 12V was the original I built.

I've added your 5V & 9V, think it's OK ...  :scratch:

I've upped C1 & C5 a bit to reflect greater load but I don't think its really required for your application.

Title: Re: Digital oscilloscope project/kit
Post by: John Swift on December 31, 2015, 12:20:48 PM
Hi Rob

I see you have been busy

the kits you have built should come in handy

looking at the power supply
I would fit two 2200uF capacitors

one for the positive supplies and a second for the negative supply


   John

PS
I see Bluechip is quicker !!!
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 31, 2015, 12:54:36 PM
Cheers Dave and John S 

Two much improved designs , I like the modifications you made John .

Dave , yours has resistors and diodes added , in simple English why?  (anyone)


This power supply is just to run the projects I have built from Banggood , this is their recommendations for the PSU for the signal generator .

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/Signal%20Generator_zpsfbvbpioj.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/Signal%20Generator_zpsfbvbpioj.jpg.html)

I just added bodged on the 9v.


I know it is poor and a much better one could be built , I could just use the three bench PSU I have . I just  thought why not have ago at building it and learn a few things on the way , which I have done thanks to you lads  :thumbup:  and reading up on each component , f&%k lot to take in  :palm:  , also I am using it as a project to learn how  to use the  Circuit Wizard software   ,its is also something to piss about with in the   warm  :lol: 

The thing is the passed few weeks messing with these boards has got my interest up in learning electronics  :med:  ,tis all up hill from here  :palm:

Dave , what electronics program are you using ? 


Thanks again for your input Lads  :bow: , keep it coming  :poke:


All the best Rob  :beer:


Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on December 31, 2015, 01:19:10 PM
Resistors are to discharge the 2200uF caps. Just considered good practice.

Diodes there to protect regulators from inadvertent connection of reverse voltage from external circuitry. [ If you use PSU for experimenting, anything can happen  :zap: Done it. Also, I did use the PSU to drive a small 24VDC motor, all sorts of spikey crap comes off them ].

You should really put more diodes across the regulators to prevent damage by putting volts on the o/p with no power to i/p. Regulators don't like it up 'em the wrong way ...  :thumbup:  I will amend schematic to show this. Also I notice some wrong component numbering ...

Program is Express PCB. Comes in 2 parts. Schematic and PCB layout. Been mentioned before in this thread, does not export full Gerber file but I etch PCBs myself so it's OK for me. Used to do Eagle but it has a size limit Express PCB does not.

http://www.expresspcb.com/

Dave
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on December 31, 2015, 01:39:59 PM
Amended schematic:

This sort of thing is quite common. They all do the same job. Take the 9V regulator.

[1] The 1N4004 across the output. If I shove a reverse voltage into the output, the diode will conduct and effectively prevent any reverse voltage greater than some 0.6V appearing across the o/p to 0V. The regulator lives on.

[2] The 1N4004 connected across the regulator, output to input. If I shove a normal polarity voltage into the output with no volts on the input, the diode will conduct and charge the input capacitor. The reverse voltage across the regulator is again limited to some 0.6V and again the regulator survives.

Regulators don't like outputs higher volts than inputs or outputs lower volts  than ground. They often exhibit their displeasure by snuffing it. Bugger eh ??

If you consider it's not going to happen D1 - D8 can be left off, no problem, it'll work just fine without.  :clap:

Dave
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 31, 2015, 01:47:06 PM
Cheers Dave ,

Getting There with this software .

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/Circuit%20Wizard%20-%20Power%20Supply_zpsz5qbitvi.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/Circuit%20Wizard%20-%20Power%20Supply_zpsz5qbitvi.jpg.html)


It must be beer O'clock  :beer:



Rob 
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on December 31, 2015, 01:54:40 PM
Cheers Dave ,



It must be beer O'clock  :beer:



Rob

What a coincidence, my clock says just the same ...  :beer: Must have batteries from the same batch.

Dave
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 31, 2015, 01:58:39 PM
 :) :thumbup:


Rob  :beer:
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on December 31, 2015, 02:35:10 PM
Rob,
Make the tracks as thick as they can be.....


Then fill the voids with a copper fill......etching a board wont take as long as theres less to etch away...
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on December 31, 2015, 04:17:43 PM
Hi all
I received the smd practice board this morning and have finished most of it.
I haven't soldered the transistors or the IC yet as they play no part in the test circuit, however putting 15 volts through it lights the LED so I did something right.

I will solder them in anyway just for more practice because there is an IC on the scope board.

It was reasonably  easy much to my surprise, the 0603 resistors were the hardest but they all went on OK.

I now have the confidence to press on with the scope kit and the tester kit.

I'll see if I can get a decent pic to show.

cheers
Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on December 31, 2015, 04:25:44 PM
Nice one Roy

Good to hear the SMD soldering practice went ok  :headbang:  you must have bloody good eyes.

Rob  :beer:
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on December 31, 2015, 04:31:07 PM
When it comes to soldering the ic to the board......Do Not be tempted to solder all the pins on one side one after another......

If its a qfp (quad flat pack, bit like mfi furniture..... :lol:)  solder the 4 corner pins first to secure to the board nice and level.....Then solder alternate pins on each side.....This will prevent the chip from overheating...if you are a bit overzealous with the solder, use solder wick to draw off the excess solder...dont use a solder sucker....risk of damage to chip or pcb.....
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on December 31, 2015, 04:47:46 PM
No, I've got a 5"magnifier lamp with a shedload of LED's round the edge. :thumbup:
It makes a hell of a difference, those 0805's looked like house bricks.

I think if I ever had to solder 0603's again I need a smaller chisel tip for the iron. the smallest one I have is 2.4mm and I could get a 1.2 or a 0.8.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on December 31, 2015, 04:50:44 PM
I would suggest the 0.8mm tip. That's what I have on my Weller. Even that seems too big sometimes and I don't even do SMT.

Dave
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on December 31, 2015, 05:05:29 PM
Hi Dave,
I've just ordered a 1.2 and a 0.8 straight after my last post.

the IC lands on the practice board are only 0.8 so anything bigger is going to be too big.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on January 01, 2016, 03:37:25 AM
Here you are, Rob ...

PCB for your PSU, not including diodes & LEDs ..

Done on ExpressPCB. Took about an hour.

Dave

Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 01, 2016, 04:25:13 AM
Morning and a happy new year to you  Dave   :wave:


You missed off my transformer lol , Your layout looks allot more efficient / better than mine  :thumbup: , I like the way you laid  out the  regulators .


All the best , Rob   
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 01, 2016, 04:29:25 AM
Happy new year all.......  :thumbup:

Nicely done Dave... :bow:

Rob, the tranny connections are at the lhs side of the board..... To the left of the bridge...

If I were building it, I'd use a Molex 3 pin plug on the transformer leads, and use a matching 3 pin header on the board...a much neater approach rather than direct wiring but to each his own.... :D
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on January 01, 2016, 04:34:53 AM
And a Happy and Prosperous New Year to you Gents ...  :nrocks:

If I were doing it, I'd use a PCB mounting transformer ...   :thumbup:  like this:

http://cpc.farnell.com/camdenboss/ctfp6-12/transformer-6va-2x-12v/dp/TF01362

but as we seem to be stuck with a snivelling bit of a 3VA Chassis transformer I decided to make the rest of it look a bit Neolithic to suit ...  :lol:  :lol:

A bit nippy here ..  :(  not going out today  .... no sireeeeee 

Dave
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 01, 2016, 04:45:20 AM


Rob, the tranny connections are at the lhs side of the board..... To the left of the bridge...



Morning and all the best  John , I did see the connector for the transformer  :thumbup:,  I want my massive 3VA on the board   :dremel:



If I were doing it, I'd use a PCB mounting transformer ...   :thumbup:  like this:

http://cpc.farnell.com/camdenboss/ctfp6-12/transformer-6va-2x-12v/dp/TF01362

but as we seem to be stuck with a snivelling bit of a 3VA Chassis transformer I decided to make the rest of it look a bit Neolithic to suit ...  :lol:  :lol:



Dave


Hi dave , whats my poor wee transformer ever done to you  :lol: :lol: :lol:

http://www.rapidonline.com/Electrical-Power/Blore-Bowron-A5004-PCB-Transformer-115V-115V-3VA-12V-12V-88-5350    ,  :)




Rob

Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on January 01, 2016, 06:40:19 AM
So, not a chassis transformer ???

Oh well, another wrong idea I've got.  :doh:     I blame Global Warming. I was OK until that kicked in ... must have addled my brain  :scratch:

I've made templates for the CPC trannies .

So it would be quite possible to mount it on the board.

Dave
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 01, 2016, 07:30:27 AM
Hi, just a quick pic of my test board.
(http://i293.photobucket.com/albums/mm72/wheeltapper_2008/test20board_zpshybj1zrh.jpg) (http://s293.photobucket.com/user/wheeltapper_2008/media/test20board_zpshybj1zrh.jpg.html)

it's not too bad, at least the LED works. :zap:

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 01, 2016, 07:32:32 AM
Rob,
ESR do a line in pcb trannies.......but I guess you aleeady knew that.....

They aint to far from you either at Cullercoats....( boy I love going to that place....lots of luverly conponents.... :lol:)

Roy,
Looks pretty good....( for a beginner.... :lol:) for a first attempt....

I have to admit when I'm reworking a board, the thinnest solder I have is .8 mm and I think thats too big...I ought to buy some paste really, but I'm a tight Yorkshireman...you know... :clap:
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 01, 2016, 08:06:06 AM
Thanks John.
It is the first time I've used SMD's, I used 0.8mm on the 0603's and 0.7mm on the rest.

Considering that when I look at the board without my glasses I can't even see the damn components I'm quite pleased.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 01, 2016, 08:16:47 AM
So, not a chassis transformer ???

Oh well, another wrong idea I've got.  :doh:     I blame Global Warming. I was OK until that kicked in ... must have addled my brain  :scratch:

I've made templates for the CPC trannies .

So it would be quite possible to mount it on the board.

Dave


Nope PCB mounted Dave as I shown  about 5 back .

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/Circuit%20Wizard%20-%20Power%20Supply_zpsihbvhhty.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/Circuit%20Wizard%20-%20Power%20Supply_zpsihbvhhty.jpg.html)



Rob
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 01, 2016, 08:20:17 AM
Looking good Roy  :thumbup:


Looks like you will have no problems doing the SMD on the oscilloscope board . :dremel:




All the best Rob
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 01, 2016, 08:27:11 AM
Rob,
ESR do a line in pcb trannies.......but I guess you aleeady knew that.....

They aint to far from you either at Cullercoats....( boy I love going to that place....lots of luverly conponents.... :lol:)




I keep forgetting about ESR John  :bang: , they are only a few miles away .


Rob
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on January 01, 2016, 02:22:45 PM
Here you are, Rob.

PCB Tranny now in. Looks a bit messy  :scratch: 

Back to my Becks & cashews ..  :beer:

Hope I've got 'em re-sized properly.

Dave

EDIT1   Near enuff ...  :loco:
EDIT2   Each dot is on a 0.1" pitch

Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 01, 2016, 02:42:01 PM
Lookin good Dave  :thumbup:


My electronics /PCB software can't do a ground plane   :scratch:


I could not agree more ,,,,,,,,,,,,where be my beer  :beer:


Cheers Rob
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 01, 2016, 02:53:08 PM
Dave,
I know you done well...... :bow:

But I think the distances between the copper infill are a bit close around the transformer.... :scratch:

I prefer at least 6mm creepage distance for safety... :zap:

Just  my 2 cents....while drinking my Carling cider.... :coffee:    Enjoy.... :)
Title: Re: Digital oscilloscope project/kit
Post by: philf on January 01, 2016, 03:10:33 PM

My electronics /PCB software can't do a ground plane   :scratch:


Rob,

Are you sure?

I managed to do a copper pour to fill. What i couldn't do was neatly connect a pad to the plane. I've uninstalled it now so can't tell you exactly how to do it.

 :beer:

Phil.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 01, 2016, 03:16:45 PM

My electronics /PCB software can't do a ground plane   :scratch:


Rob,

Are you sure?

I managed to do a copper pour to fill. What i couldn't do was neatly connect a pad to the plane. I've uninstalled it now so can't tell you exactly how to do it.

 :beer:

Phil.


Hi Phil

I think I am driving it correctly , I added the copper fill but I cant connect to it  :scratch: ,  I thought just add the copper fill ,then remove/delete  all the traces that are at 0 volts , but it just isolates the pads .


how did you get a connection ? 


Cheers Rob  :beer:
Title: Re: Digital oscilloscope project/kit
Post by: philf on January 01, 2016, 03:30:19 PM

My electronics /PCB software can't do a ground plane   :scratch:


Rob,

Are you sure?

I managed to do a copper pour to fill. What i couldn't do was neatly connect a pad to the plane. I've uninstalled it now so can't tell you exactly how to do it.

 :beer:

Phil.


Hi Phil

I think I am driving it correctly , I added the copper fill but I cant connect to it  :scratch: ,  I thought just add the copper fill ,then remove/delete  all the traces that are at 0 volts , but it just isolates the pads .


how did you get a connection ? 


Cheers Rob  :beer:

Rob,

You have to draw a track from the pad to the filled area. (I found somewhere in the help that told me that was the only way.)

I found this in one of their tutorials which shows the filled area but no connections to any pads.

(http://listerengine.com/coppermine/albums/userpics/10017/PCBWiz_zpsuue02lhh.jpg)

I don't know if you can get sufficient clearance for the pads for your transformer or whether you're stuck with a standard clearance. There will be a way round it I'm sure.

Other software allows you to specify on the pad properties if it's isolated or not.

In my PCB I used one plane for 0v to connect to my Pi and one plane for the 0v from my proximity sensor inputs. I wanted to keep both sides completely separate to keep the 24v away from the Pi which is limited to 3.3v on the inputs.

 :beer:

Phil.
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on January 01, 2016, 03:40:17 PM
Dave,

But I think the distances between the copper infill are a bit close around the transformer.... :scratch:

I prefer at least 6mm creepage distance for safety... :zap:


Yes, quite right, there should be more clearance.

Did it when I was sober, [ or very nearly ], brain would be lacking some essential toxin and thus not on top form.

Rectified now. Back on full power, like a re-gunned CRT.

Dave

Title: Re: Digital oscilloscope project/kit
Post by: modeng200023 on January 02, 2016, 09:22:01 AM
I have been following this topic with much interest.

Rob and John or anyone else with experience of using this scope, after using it for a while do you have any reservations bearing in mind that it is resonably priced?

The other thing I'd like ideas on is a case for it if anyone has thought about ready made ones.

John
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 02, 2016, 10:01:55 AM
I have been following this topic with much interest.

Rob and John or anyone else with experience of using this scope, after using it for a while do you have any reservations bearing in mind that it is resonably priced?

The other thing I'd like ideas on is a case for it if anyone has thought about ready made ones.

John

Hi John

    15 delivered its a cracking bit of fun ,it has  nowhere near  the capabilities of a good or even low end bench DSO ,but  for 15 I really can't find fault .

It has also generated a good bit crack on the forum and lead to other topics like a 3DP case , so if you could CAD model a case maybe someone could print one for it ,  I may stick mine in an ally

case , I bought longer bush buttons that come level with the screen , I just need to find away to bring the slide switches forward .


or there is this kits .

http://www.banggood.com/DSO068-DIY-Oscilloscope-Kit-With-Digital-Storage-Frequency-Meter-ATmega64-AVR-Microcontrol-p-981017.html


More than double the price ,but it has a case .


Maybe the more experienced chaps could chip in with some oscilloscope advice  :thumbup:



Cheers Rob




   
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 02, 2016, 10:14:11 AM
I see Bangood now supply a PSU fo the DSO  2.28   http://www.banggood.com/DSO138-Power-DCDC-Converter-Boost-Module-Step-up-Module-Board-p-1000089.html   :zap:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: modeng200023 on January 02, 2016, 12:59:51 PM
Thanks Rob, I think I'll have some fun.

John
Title: Re: Digital oscilloscope project/kit
Post by: John Swift on January 05, 2016, 03:36:49 PM
Hi Rob

a simple LED oscilloscope from 20 years ago

the circuit shows the principle

the 'scope in the  photo has an adjustable sync  , time base and attenuator
as expected in a usable  tool
the oscilloscope is usable up to 30 KHz

    John

Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 05, 2016, 03:43:57 PM
John,
There arent any valves in that design..... :lol:
Title: Re: Digital oscilloscope project/kit
Post by: John Swift on January 05, 2016, 03:52:33 PM


Hi  John

    your correct ,
I did not go back to the old all valve Heath Kit oscilloscopes or Practical Wireless projects

they don't work with just a pp3 battery

     John
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on January 05, 2016, 04:12:49 PM
If you care for a quick wallow in nostalgia:

https://archive.org/stream/PracticalWireless1971April#page/n25/mode/2up        :thumbup:

Dave

PE archive  a few ..

https://archive.org/search.php?query=practical%20electronics
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 05, 2016, 04:17:02 PM
If you care for a quick wallow in nostalgia:

https://archive.org/stream/PracticalWireless1971April#page/n25/mode/2up        :thumbup:

Dave

Yup, remember that well......iirc there was another scope in one of the other periodicals a couple of years earlier....Radio Constructor? Used a 1CP1 crt....iirc..

I love nostalgia and wallowing....
Title: Re: Digital oscilloscope project/kit
Post by: awemawson on January 05, 2016, 04:34:20 PM
Made my first oscilloscope when I was at school based on an ex WW2 VCR97 radar tube 6" diameter. Drove the metal working instructor mad pestering him to help me make the chassis and front panel. Used many of the ubiquitous EF50 red metal canned valves that the surplus shops were awash with at the time

http://www.r-type.org/exhib/aaj0166.htm

http://www.dos4ever.com/EF50/EF50.html

It worked ok but the frequency response was pretty low at about 1Mhz
Title: Re: Digital oscilloscope project/kit
Post by: sparky961 on January 05, 2016, 11:09:27 PM
Hi, just a quick pic of my test board.
it's not too bad, at least the LED works. :zap:
Roy.

Seems a little Rube Goldberg if you ask me... ;)
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on January 06, 2016, 02:21:18 AM

I love wallowing....


You  be careful. I reckon it was too much wallowing in my younger days that did my back in.  :ddb:

Dave
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 06, 2016, 02:34:29 PM
Hi Rob

a simple LED oscilloscope from 20 years ago

the circuit shows the principle

the 'scope in the  photo has an adjustable sync  , time base and attenuator
as expected in a usable  tool
the oscilloscope is usable up to 30 KHz

    John



Hi John ,  Did you build one ? 


Looks a fun project , I may have a bash at making one myself   :zap: 



Its good to see this old time technologie , all way way before my time    :lol: :lol:                 cheers for sharing lads  :thumbup:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 06, 2016, 03:27:03 PM
Hi Rob.
I've just finished building the scope kit and it all seems to work OK apart from one thing, the top l/h switch for AC, DC and ground, I can only get the display to indicate DC or ground.
have you any ideas what to look for?

cheers
Roy.
Title: Re: Digital oscilloscope project/kit
Post by: kayzed1 on January 06, 2016, 04:01:13 PM
My kit arrived today, will take a look at it in the morning and report back.
Lyn.
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 06, 2016, 05:21:52 PM
How long does it take for a kit to arrive?

Might just buy one for fun... :coffee: I already have a digital lcd scope...... :scratch:
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 06, 2016, 05:49:24 PM
Hi Rob.
I've just finished building the scope kit and it all seems to work OK apart from one thing, the top l/h switch for AC, DC and ground, I can only get the display to indicate DC or ground.
have you any ideas what to look for?

cheers
Roy.

Hi Roy

All I can think of is you may have a faulty switch  ,



From pin 2 on the back of the board to the outer of the BNC plug ,

 (http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/1_zpskuqqpncw.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/1_zpskuqqpncw.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100791_zpschhqsxrb.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100791_zpschhqsxrb.jpg.html)

With the switch  in the Ground position you should have continuity .


(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100792_zpsmt90nwrp.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100792_zpsmt90nwrp.jpg.html)
 

In AC or DC there will be a high resistance , if you still have continuity in these positions the switch is bust. 



DSO  Manual attached for the pros to cast an eye over .


Hope that helps ,Rob 
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 06, 2016, 05:55:14 PM
How long does it take for a kit to arrive?

Might just buy one for fun... :coffee: I already have a digital lcd scope...... :scratch:

Mine arrived within a week. ordered on 21-12, e-mail saying it was dispatched 22-12, arrived a few days later.
I got mine from here
http://www.ebay.co.uk/itm/131575205359

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 06, 2016, 05:58:48 PM
How long does it take for a kit to arrive?

Might just buy one for fun... :coffee: I already have a digital lcd scope...... :scratch:


You know you want to John  :poke:  ,,,,,,,,,,,,,,,,,,,,,,join the fun  :lol:



Rob

4 weeks from banggood  :palm:
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 06, 2016, 06:06:29 PM
Rob,
I just checked the switch and I get what you say on pin 2, continuity to ground, high resistance on AC or DC.
why is there an arrow pointing to pin 4?

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 06, 2016, 06:23:15 PM
Rob,
I just checked the switch and I get what you say on pin 2, continuity to ground, high resistance on AC or DC.
why is there an arrow pointing to pin 4?

Roy.


Hi Roy

 Pin 4 is connected to BNC outer ,it was easier/clearer  to use a crock clip on the connector and take the photo .

So its not the switch then . mmmmmmmm


Rob


Title: Re: Digital oscilloscope project/kit
Post by: John Swift on January 06, 2016, 06:26:16 PM
Hi Rob

just got back from the Everton v Manchester City match    (we won 2-1)

no I didn't build the LED scope
 I built a Vellerman LCD scope about 12 years ago
I've not used it for a while it needs the  6  AA nicads replacing

   John


Title: Re: Digital oscilloscope project/kit
Post by: John Swift on January 06, 2016, 07:16:03 PM
Hi Roy

just double checking
when you say I can only get the display to indicate DC or ground.

do you mean it does not show "AC" at the bottom of the LCD
or the trace is a straight line

if its not indicating "AC" at the bottom of the LCD then check the voltage at test point TP6  ( switch 1B terminal 6 )
+5V for DC
 +1.2V  for AC
and 0V for GND

if its the trace not responding
check C1 is 0.1uF (marked 104)
if for instance a very small value capacitor that should be C2 , C3 , C5 or C7
virtually non of the AC voltage at the input connector will be passed onto  switch 1A terminal 3

   John
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 07, 2016, 06:07:18 AM
Hi John, thanks for the reply.

It is the indicator on the LCD, it doesn't change to AC.

I was going to do some voltage checks as soon as real life gets out of the way. :bang:
I'll get back with the results.

Cheers
Roy.
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 07, 2016, 06:24:42 AM
Thar's interesting, I'm getting 3.8v on AC.

I will look further.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: Will_D on January 07, 2016, 07:31:55 AM
DSO  Manual attached for the pros to cast an eye over .
Hope that helps ,Rob
Cheers Rob for posting the manual.

 I must say that is one of the best manuals I've seen in a while for such a cheap kit!.
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 07, 2016, 07:37:33 AM
3.8v is too high....should be around 1.4v.....it looks like the software isnt switching as a result...

I suspect the resistors are the wrong way round....

You need to check the values of the resistors in the chain......
Title: Re: Digital oscilloscope project/kit
Post by: John Swift on January 07, 2016, 08:00:50 AM
Hi Roy

the voltages measured will depend in the input current into pin 13 of the micro controller
but this picture shows  what I expect

   John


Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 07, 2016, 08:57:26 AM
Typical! I get that fixed and now the trace is stuck at the bottom of the screen. :doh: :doh:
It won't any how I try.

Roy.

EDIT
test point V1 is now -1.4V instead of 0.test point V2 has also gone negative.
Title: Re: Digital oscilloscope project/kit
Post by: John Swift on January 07, 2016, 10:12:16 AM
Hi Roy

what did you re work to fix the original problem ?

with switch 1 grounding the input
pins 1 , 2,  3 , 4 on switch 2 (SEN1) should all be at 0V
 the switch common (pin2) is connected to the input pin 5 of the unity gain buffer U2B
the voltage at TP 2 should be the same

possibly a splash of solder is shorting some thing to the negative supply AV-

  John

PS

how negative is TP2
just noticed U2 negative supply pin 11 is next to pin 10 U2C's input
 which is connected to switch SEN2 's common

Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 07, 2016, 10:49:12 AM
Yippee.
I think I've fixed it.
the first thing I did was reflow R18, that fixed the AC problem.

I just reflowed pins 1 to 7 on IC U2 and all the voltages are correct now.

PHEW!

thanks for the help.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 07, 2016, 10:56:10 AM
Yippee.
I think I've fixed it.
the first thing I did was reflow R18, that fixed the AC problem.

I just reflowed pins 1 to 7 on IC U2 and all the voltages are correct now.

PHEW!

thanks for the help.

Roy.

Excellent! Glad you fixed it... :zap:
Title: Re: Digital oscilloscope project/kit
Post by: John Swift on January 07, 2016, 11:11:02 AM

great news

your perseverance paid off


   John

Title: Re: Digital oscilloscope project/kit
Post by: shipto on January 07, 2016, 03:54:17 PM
I am cracking on with mine but ran into a problem on the surface mounted resister 20. I couldnt get the solder to take and after a few tries the pad came loose.
It looked to me like the connection is to the large area under the R20 so I scratched a little of the paint away and bridged the solder to that but it would be nice if someone could confirm that this is the right thing.
Title: Re: Digital oscilloscope project/kit
Post by: John Swift on January 07, 2016, 04:57:28 PM
I've not found a good photo showing the PCB without R20 and R21 fitted
but I've highlighted the connections you should have

If all else fails it should be possible to fit wire ended resistors directly to the terminals on switch SEN1 to replace the surface mount resistors

   John
Title: Re: Digital oscilloscope project/kit
Post by: sparky961 on January 07, 2016, 07:31:19 PM
I suspect the resistors are the wrong way round....

Sure this doesn't belong in the "cruelty to apprentices" thread? :poke:
Title: Re: Digital oscilloscope project/kit
Post by: kayzed1 on January 07, 2016, 08:25:07 PM
i have not started mine as yet, my Iron has too large a tip to get into these small spaces so i need to order a new small iron 30w i think it said. My only good iron is 60watt and big, from my BT days.
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 08, 2016, 05:25:12 AM
I suspect the resistors are the wrong way round....

Sure this doesn't belong in the "cruelty to apprentices" thread? :poke:

I had a chuckle when I read that.
I know he meant I may have transposed two resistors, it just came out wrong. :D...........................................................at least, I hope that's what he meant. :lol: :lol:

unidirectional resistors, whatever next.
the mind boggles.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 08, 2016, 05:37:28 AM
Quote from: wheeltapper

I had a chuckle when I read that.
I know he meant I may have transposed two resistors, it just came out wrong. :D...........................................................at least, I hope that's what he meant. :lol:

Roy.

Yes that is what I meant...10k at the bottom, 3.3k at the top.....
Title: Re: Digital oscilloscope project/kit
Post by: shipto on January 08, 2016, 05:42:44 AM
Thanks John I will check that later when I am in shop.
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 08, 2016, 06:26:43 AM
Thanks John I will check that later when I am in shop.

Just to be clear here......

I thought you may have got the two resistors transposed, and that was why the readings were wrong....but as you said in a previous post, the joints were not good and you reflowed some of them.

So as the resistors appear to be correctly placed, that is the 10k is connected to 5v and the 3.3k is connected to 0v, the junction provides the third state for AC indication.....

As it is all working ok now, you dont need to fault find anymore.... :zap: :)
Title: Re: Digital oscilloscope project/kit
Post by: shipto on January 08, 2016, 07:01:53 AM
No John your confusing me with someone else I just had pad come loose is all so far
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 08, 2016, 12:11:22 PM
No John your confusing me with someone else I just had pad come loose is all so far

Hmm...so I have.... :scratch: my apologies....in my defence, I plead a senior moment.. :lol:
Title: Re: Digital oscilloscope project/kit
Post by: shipto on January 08, 2016, 06:19:17 PM
No John your confusing me with someone else I just had pad come loose is all so far

Hmm...so I have.... :scratch: my apologies....in my defence, I plead a senior moment.. :lol:
My fault couldnt figure out how to quote message with tapatalk.
Title: Re: Digital oscilloscope project/kit
Post by: kayzed1 on January 09, 2016, 03:13:48 PM
Whilst on the subject of Banggood stuff, i made the PSU but am short of the 22volt AC input...still looking for that.
So i moved on to the trany tester and have it all together barring one item missing, the  ( i think ) ceramic cap with
104 printed on it, i do have one extra three leg with a number that includes 104 so i think they have dropped a thingy.
I also have what looks to be the same thing spare in another kit with 104 printed on it but it is a little bigger and a
more yellowy Orange, the original item is a more Orange orange if that makes sense..
Lyn.
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 09, 2016, 03:41:29 PM
So, you mean you need a 22v ac secondary transformer?

Which psu is this?

Can you post up a picture of your 104 thingy?.....Generally speaking a 104 thingy with 2 legs is going to be a capacitor with a value of 0.1 mfd or 100 nF, if the board reference begins with C....three legs....hmmmm not sure what that could be :scratch:.....A mutant 100n cap...with 3 legs...  :lol:
Title: Re: Digital oscilloscope project/kit
Post by: DMIOM on January 09, 2016, 04:09:17 PM
..........three legs....hmmmm not sure what that could be :scratch:.....A mutant 100n cap...with 3 legs...  :lol:

Oi !    :poke:    we're unique on the Isle of Man, not mutants!

(https://upload.wikimedia.org/wikipedia/commons/thumb/b/bc/Flag_of_the_Isle_of_Man.svg/600px-Flag_of_the_Isle_of_Man.svg.png)
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 09, 2016, 04:16:00 PM
If the BG psu is the one Rob referred to, it has some flaws.....
The max ac input is 24 AC, rectified will give around 36 v at the reservoir cap.....this is right on the edge for the TLO op amps used in the design.....
Title: Re: Digital oscilloscope project/kit
Post by: kayzed1 on January 09, 2016, 04:38:56 PM
that is it John the one Rob has, can't do pics as my internet is soooo slow, but will try tomorrow some time late when the kids are in bed and the net not so busy,, tis a little diddy cap.  It uses three that look the same but have the number range 101, 103 and 104, as said will try a pic tomorrow.
Thanks.  Lyn.
Title: Re: Digital oscilloscope project/kit
Post by: drmico60 on January 09, 2016, 05:38:31 PM
With a few more legs and a tyre you might have invented the wheel!
Mike
Title: Re: Digital oscilloscope project/kit
Post by: PekkaNF on January 09, 2016, 06:05:51 PM
Clacking bell!

I was minding my own business, measuring DIY spotwelder controller with a transformer and doublecheccked each time all is fine....Then it got time to measure thyristor and ofcourse I checcked that scope body was "zero" and same "zero" that line that feeds the thyristors.

I put the shuko on  :zap:

Yup this outlet could go either way...I though I did not fiddle with it. Wife noticed that fuse blew, because outlet from that bedroom went off too. I was affraid that that I fried the scope, but noooooo.....Just good oldfachioned scope "ground" to phase error :doh: :doh: :doh:

OK. This scope is nowwhere as good as these beauties, but maybe it's easier to float.

Pretty german Phillips (Two tubes, othervice transistors) does not sync. I got one nearly as old UK made one and that mostrly works...

Where you get 1:1 and 1:10 scope probes?

Pekka
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 10, 2016, 04:35:43 AM
Whilst on the subject of Banggood stuff, i made the PSU but am short of the 22volt AC input...still looking for that.

Lyn.

Hi John

I think Lyn is referring to  the 0 - 30 v PSU    http://www.banggood.com/0-30V-2mA-3A-Adjustable-DC-Regulated-Power-Supply-DIY-Kit-p-958308.html  , info attached .

My 0 - 30 v psu kit arrived yesterday along with the frequency meter kit  :zap:






Rob
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 10, 2016, 04:49:09 AM
Hi Rob

just got back from the Everton v Manchester City match    (we won 2-1)

no I didn't build the LED scope
 I built a Vellerman LCD scope about 12 years ago
I've not used it for a while it needs the  6  AA nicads replacing

   John



Hi John

That looks a canny project , shame the kit is no longer available .


I dont do football  I prefer things with two wheels and an engine  :thumbup:  ,,,,,,,,,,,,,,the wife is a big Toon sports direct supporter   :lol:


Rob




Title: Re: Digital oscilloscope ,PSU,component tester and other electronics kits
Post by: RobWilson on January 10, 2016, 05:02:10 AM
While on the subject of PSU  , I bought the  0-30v PSU kit and it needs a mains transformer .

240v to 24v 

3 amp max

Would this one from ESR do the job   p#  311-312       https://www.esr.co.uk/electronics/products/frame_transformers.htm   

 



Cheers Rob

 
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 10, 2016, 05:05:13 AM
Yippee.
I think I've fixed it.
the first thing I did was reflow R18, that fixed the AC problem.

I just reflowed pins 1 to 7 on IC U2 and all the voltages are correct now.

PHEW!

thanks for the help.

Roy.


Good to hear you got it sorted Roy  :thumbup:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 10, 2016, 05:11:38 AM
If the BG psu is the one Rob referred to, it has some flaws.....


John while searching the Banggood site I came across the PSU for the signal generator , a tad better than the suggested  one in the manual , I will still make the suggested one as I have the parts .

Anyway  http://www.banggood.com/DIY-USB-Boost-Single-Turn-Dual-Power-Module-Linear-Regulators-Multiple-Output-Power-Kit-p-1022517.html   , on order .

Input voltage: 5-24V DC
Output voltage: + 12V, -12V, + 5V, -5V , +3.3V.
Output current: 300mA (per channel)


Rob
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 10, 2016, 05:15:55 AM
Rob,
There ara number of issues with that power supply kit, not least of all tha fact that a transformer with a 24 v ac secondary is going to give something like 36 v dc across C1...
Plus there is around 5v across D7.... This is totaling some 40 plus volts powering the three op amps...These are TLO81's with a maximum supply of 36 across their supply terminals....Result?  :zap:
Thecanswer to this problem is use op amps with a higher operating voltage or use a transformer with a lower secondary voltage....

To answer your transformer question, the voltage is too high, see the above....and the current rating too low to expect 3 amps from the power supply.....

If the shortcomings of the design are overcome, then a transformer with at least a va rating of 100 watts is needed....( dont forget the power supply is 'supposed ' to be good for 30 v x 3 A or 90 watts...realistically a 120 watt rated transformer is needed.....

If you want to run the power supply as designed, then go for a transformer with a lower secondary voltage.....but then that cant becallowed to go too low else the Negative voltage rail charge pump circuit wont give the designed voltage.....(C2,C3,R2 R3, D5/D6)
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 10, 2016, 05:40:45 AM
My bad John

I copied wrong part number    :Doh:    , I meant this one   p#   312-612   12 - 0 - 12 3A 72VA Chassis Transformer   

So you reckon the op amps need upgrading , any recommendations mate . 

Rob
 
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 10, 2016, 05:56:55 AM
Anyway to small ,   why use VA ?    is VA just Watts ? 


volts  x amps .


Rob
Title: Re: Digital oscilloscope project/kit
Post by: awemawson on January 10, 2016, 06:11:21 AM
VA is WATTS with the Power Factor taken into consideration. Power Factor relates to the way the phase of the voltage and current vary. Typical PF of a motor is 0.8


https://en.wikipedia.org/wiki/Power_factor

http://www.power-solutions.com/watts-va
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 10, 2016, 06:20:01 AM
Hi Andrew


so if an electric motor was    240v x8A x 0.8 pf =  1536 VA or near enough 1.5Kva  ,  any idea what the power factor of a transformer would be ?  is that another can of worms lol


Rob 
Title: Re: Digital oscilloscope project/kit
Post by: awemawson on January 10, 2016, 08:16:52 AM
Big transformers have PFs nearer to unity whereas little ones can be as low as 0.5 - it depends how much trouble they went to designing the magnetic circuit

http://www.the-power-factor-site.com/Transformer-Capacity.html
Title: Re: Digital oscilloscope project/kit
Post by: shipto on January 10, 2016, 11:52:57 AM
Mine lives  :ddb:
2 pics one with the self generated signal and the second with the signal generated by my other oscilloscope.
sen1 switch is a little temperamental it needs jiggling a little to work properly but I will live with that.
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 10, 2016, 02:43:45 PM
In answer to Rob's question on the 0-30 v power supply....

Any one cinsidering building this, my recommendation fwiw .......http://www.ti.com/lit/ds/symlink/opa445.pdf

These op amps have a better survival rate at 43v than the orig TLO81's originally specified.....
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 11, 2016, 02:32:31 PM
Cheers John  :thumbup:  , I may  getting a few for the PSU kit .

Nice one Shipto  :clap: :clap: good to see another up and running , do you or has anyone else who has built one of these DSO have any thoughts on a case  ?


Cheers Rob
Title: Re: Digital oscilloscope project/kit
Post by: John Swift on January 11, 2016, 02:56:51 PM

well I've a bag of bits for the scope ordered

not decided if I should mount the capacitors and wire ended resistors on the back of the board so the display will fit closer to the main PCB 

or  mount the switches on spacers of some kind to bring them up to the level of the display

    John
Title: Re: Digital oscilloscope project/kit
Post by: kayzed1 on January 13, 2016, 03:51:03 PM
Well mine got the last blob of weld today, i found a PU in the draw that did 2V-6v-9v and 12volts so i used that to do the tests..
All worked as it should :bugeye: fitted the LCD and fired it up....we have light and pictures :clap: THEN!!! the trace went off, the rest of the screen is still lit up and all symbols are present. So i followed the trouble shooting giude and came up with two voltage errors.. L1 should be Neg 8.11volts but ut is high at 11.57 volts.  TP25 should be neg 8.08volts but it to is high at 11.56volts.
i have checked all the resistors and all are in the correct places...any thoughts?
Lyn.
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 13, 2016, 04:10:01 PM
Lyn,
I suspect the scope has suffered a death blow.....your wall wart thing must have too many ziggies coming out......

Things to check:

The voltage at TP 20 needs to be near that indicated on the schematic........

Check the voltages around TP21 and TP23....
Measure the voltages around Q1 and Q2...
Title: Re: Digital oscilloscope project/kit
Post by: John Swift on January 13, 2016, 04:17:41 PM
check the 3v3 at TP23  this is the reference at one end of R42 (1K)

the junction of R41 and R42 is the feedback voltage going to the V-MON input of U1

an error at V-MON =  TP13 =  pin 16 affects the actual voltage at TP25 the -8V supply

the actual voltages measured  depend on the positive supply at J 9 and J10

I'd expect the voltage on TP13 to be about +2V when the -8V switching supply circuit is working correctly
Title: Re: Digital oscilloscope project/kit
Post by: John Stevenson on January 14, 2016, 01:56:49 PM
Just got one of the transistor / components checkers delivered from China.
Bought the ready made up on as it was only a quid more than the kit ???

However no paperwork or instructions, anybody got a link to some somewhere ?
Title: Re: Digital oscilloscope project/kit
Post by: kayzed1 on January 14, 2016, 02:59:20 PM
Many thanks all, i will have a play on Friday.
John S, PM me your address i got two sets of destructions in my pack i will stick them int post.
Lyn.


Ow! John R, does that mean ( the high volts ) that the scree will be an EX- screen now?
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 14, 2016, 03:33:59 PM
Lyn,

Not the ex - parrott sketch.... :lol:

The extent of any overvolts damage cannot be determined without further checks and possible component replacement to resolve the existing problems...
Title: Re: Digital oscilloscope project/kit
Post by: Fergus OMore on January 14, 2016, 03:48:07 PM
For two quid at a fair some years back, I bought Telequipment Serviscope Minor that 'lights up' has wiggly green lines. Needs another probe( my limit of present skill) so can I get instructions that a near idiot could understand or should I dump it please?

Hopefully, I haven't pee'd on your parade.

Regards

Norman
Title: Re: Digital oscilloscope project/kit
Post by: John Swift on January 14, 2016, 04:49:09 PM
after a quick web search - http://www.thevalvepage.com/testeq/telequip/servmin/servmin.htm

its a bit older than the scopes I was thinking of

found some service info
http://www.gd7rvp.co.uk/uploads/1/9/5/0/19504259/serviscope_minor.pdf

after looking at fleabay   I'd say don't dump it straight away
you could find someone  daft enough to pay a lot more money  than I expected

is this the info you are looking for ?
http://www.owlnet.rice.edu/~phys112/Lab/oscilloscope.pdf

    John
Title: Re: Digital oscilloscope project/kit
Post by: Fergus OMore on January 14, 2016, 05:52:11 PM
Gosh John, you are doing well, having been born in 1667!  Seriously, thank you for taking time to help me

Cheers

Norman
Title: Re: Digital oscilloscope project/kit
Post by: John Swift on January 14, 2016, 06:58:55 PM
 
Hi Norman

no problem , I help when I can

I nearly was named Johnathan
I'm not that old, I'm only in my 60's but this last few weeks have felt a lot older

as a result of an old injury
I have sciatica from time to time  that make simple tasks like putting on socks a half hour ordeal
you have to keep moving and do what you can , when you can

Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 16, 2016, 10:57:44 AM
Afternoon Lads


The next Bangood project  :zap: .................. A frequency counter and crystal tester  :dremel:

http://eu.banggood.com/Wholesale-Warehouse-1Hz-50MHz-Crystal-Oscillator-Five-LED-Display-Frequency-Meter-Kit-wp-Uk-959592.html


Its a half hour job to weld the components in , :dremel:

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100804_zpsosnzxp5u.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100804_zpsosnzxp5u.jpg.html)


I tested it with a few crystals



(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100814_zpsjt2shjuw.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100814_zpsjt2shjuw.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100811_zps5wf2fnt8.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100811_zps5wf2fnt8.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100810_zpsli10ob4t.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100810_zpsli10ob4t.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100807_zpsdy6200q2.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100807_zpsdy6200q2.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100806_zpsxiz4xaxb.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100806_zpsxiz4xaxb.jpg.html)

Seams to work a charm  :thumbup:   


Cheers Rob



Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 16, 2016, 11:17:57 AM
You managed to chip off all the slag around those welded joints then Rob?  :lol:

Gotta admit, that seller does have quite a few good projects... :coffee: but I dont really need any more test gear......

Owon double beam digital scope with lcd display

2 x 30 v 3 A twin channel power supplies

Digital frequency counter

Lcd scope with frequency meter/ waveform generator

3 x UT 50 dvms etc etc.....

Aint got a bench big enough....or room for one   :lol:
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 16, 2016, 11:37:51 AM
Oh do slow down for Pete's sake :) I haven't had time to build the component tester yet, and I somehow ordered the signal generator and power supply. :Doh:

there just aren't enough hours in the day.

Still, it's too damn cold to go out and play with metal things so I suppose I have to have something to do.
Thank gawd this stuff's cheap.

Come to think of it, I can't offhand think of a use for a frequency meter, in fact, I can't think of a use for any of it but it keeps me off the street corners I suppose. :lol: :lol:

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 16, 2016, 11:59:03 AM
Roy,
Damn right about the cold....brrrrrrr 3 degrees here east of Hull....( dont burst into song...."when will I see you again...?" ).... :lol:

Went into the garage this pm, feet too cold....back into house....Might get the soldering iron out to sort some electronic stuff... :dremel: :zap:
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 16, 2016, 12:00:51 PM
You managed to chip off all the slag around those welded joints then Rob?  :lol:

Gotta admit, that seller does have quite a few good projects... :coffee: but I dont really need any more test gear......




The slag just peeled off John  :lol: :lol: :lol:  , I am finding the kits quite fun to build  , just something to mess with in the warm .  :zap:






Come to think of it, I can't offhand think of a use for a frequency meter, in fact, I can't think of a use for any of it but it keeps me off the street corners I suppose. :lol: :lol:

Roy.


 :lol: :lol: :lol:  , I have no idea either Roy ,,,,,,,,,,,,,,,,  :Doh: ,,,,,,,,,,,,,,,,,,but it did keep me out of trouble for an hour  :lol: :lol:



Title: Re: Digital oscilloscope project/kit
Post by: awemawson on January 16, 2016, 12:07:27 PM
Was it is with you lot and these electronic kits - don't you have enough to keep you busy in your workshops already  :lol:

If you've time on your hands you'd better come on down and help me with my backlog  :ddb:
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 16, 2016, 12:22:01 PM
I'll go back out to my shop when  my skin stops freezing to the machinery. :bugeye:

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: PekkaNF on January 16, 2016, 02:02:18 PM
Very tempted to buy one oscilloscope kit. There does not seem to be external triggering. I was checkking the same type two channel scopes (could use another channel for triggering and it would show the trigger point on the screen) but they were whole lot more complicated or too expensive to justify.

I checked some readymade modules too, they don't look much better on display or sampling rate.

Pekka
Title: Re: Digital oscilloscope project/kit
Post by: John Swift on January 16, 2016, 02:26:54 PM

I guess you could duplicate the Y amp up to TP3
disconnect R13 from TP3 and add a switch to select Y or external trigger source
Title: Re: Digital oscilloscope project/kit
Post by: krv3000 on January 16, 2016, 06:33:10 PM
brill
Title: Re: Digital oscilloscope project/kit
Post by: John Stevenson on January 16, 2016, 06:59:53 PM
You need a decent heater in the shop.

(http://www.stevenson-engineers.co.uk/files/woodstove5.jpg)
Title: Re: Digital oscilloscope project/kit
Post by: awemawson on January 17, 2016, 04:03:23 AM
Heated & well insulated workshop is essential if you want to play all day  :thumbup:

Down side is the running costs - just had the workshop oil tank topped up on Friday - 425 litres since August - the house only used 500 litres  :scratch:

Trouble is I have a roller shutter door that's probably 15 foot square and virtually impossible to insulate and yet still use so that is a huge thermal load. Rest of the building is very well insulated
Title: Re: Digital oscilloscope project/kit
Post by: mattinker on January 17, 2016, 05:39:02 AM
I'm getting a bit OT here for which I apologise!

Andrew,
I realise that your roller shutters are in use so my solution doesn't apply, but I found a source of free for collection high quality insulation panels to insulate my workshop. A friend of mine works as a salesman for a fridge truck body builder.  When fridge trucks try to get through bridges that are too low, crunching the front, the entire roof and side sections have to be replaced. It costs them money to get rid of the stuff, 5cm thick high insulation foam sheathed with a skin of polyester and fibreglass on both sides. In some parts it even comes with a stainless facing and tie down points. I made my double doors (twice 4m x 2m )with a large "pop hole" door in one of them. They are hung on bearings, the doors themselves are clad with wood and are a total of six inches thick!

So free to collect insulation, the only thing is I had to wait until the had a body to build! I cut the panels of the body  to sizes that needed just a little trimming when I got them home.

(http://i917.photobucket.com/albums/ad16/mattinker/P1030862_zpsensomkol.jpg) (http://s917.photobucket.com/user/mattinker/media/P1030862_zpsensomkol.jpg.html)
Title: Re: Digital oscilloscope project/kit
Post by: Joules on January 17, 2016, 06:45:07 AM
Just walked out to the workshop here....  1.3℃  lit stove and walked back into warm house and fired up CAD machine  :(
Title: Re: Digital oscilloscope project/kit
Post by: awemawson on January 17, 2016, 07:54:53 AM
Well Matthew I did ask Penny if she fancied making some very heavy curtains to help insulate the roller shutter door, but I got a VERY old fashioned look in return  :bugeye: I dropped the subject after that  :lol:

I have my oil fired central heating in the barn set to 7.5 deg C over night and 17 deg C during daytime. With our first fall of snow this year on the ground outside it hadn't managed to get to set point - sitting at 16 deg C  :(
Title: Re: Digital oscilloscope project/kit
Post by: awemawson on January 17, 2016, 07:57:07 AM
You need a decent heater in the shop.

(http://www.stevenson-engineers.co.uk/files/woodstove5.jpg)


Now we can all make a copy of your Chubb key John  :lol:
Title: Re: Digital oscilloscope project/kit
Post by: John Stevenson on January 17, 2016, 11:54:03 AM
Wouldn't do you any good Andrew. the lock was used to lock the big double doors for the INSIDE.
The insurers weren't happy that I had them secure from the inside with a big M16 nut and bolt, they won't open from the outside.
When I pointed out that once they were INSIDE they had access to plasma cutters still saws, grinders, oxy acetylene, chisels etc it went over their heads so we bought a lock just to keep them happy.

Now I have swapped companies the lock is clipped to the security bars and we are back to the M16 nut and bolt.

The other keys are for me bike lock but I have lost me bike........................
Title: Re: Digital oscilloscope project/kit
Post by: PekkaNF on January 17, 2016, 01:25:05 PM

I guess you could duplicate the Y amp up to TP3
disconnect R13 from TP3 and add a switch to select Y or external trigger source

Oh, that will clear it!

I had wrong diagram! Found all relevat parts on:
DSO 138 Oscilloscope DIY Kit
Rev. 04 Applicable models: 13803K, 13804K

Starts to look very promissing!

Thank you very much!

Pekka

Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 17, 2016, 04:05:07 PM
 :D :D :D I've spent the afternoon assembling the component tester and it's case and it appears to work perfectly. :ddb: :ddb: :ddb: :ddb:

there weren't any  :zap: :zap: either.

trying to figure out the calibration was a bit of a bugger, there are online instructions but they aren't very clear...................or I'm thick :bang:
choose whichever you like.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: hermetic on January 17, 2016, 07:21:32 PM
Andrew, I have seen curtains made from 2 layers of bubblewrap hung inside roller shutters, keeps it a lot warmer.
Phil
Title: Re: Digital oscilloscope project/kit
Post by: John Swift on January 22, 2016, 06:32:44 PM
decided to assemble my DSO138 oscilloscope kit this afternoon
it worked first time even though the solder didn't flow that well on the surface mount components - an excuse to buy a smt work station I think ?

for now I've used the switches provided but may change them when I mount it in a box
modding is a must !

two things needs investigating
the variable capacitor C6 does not appear to do much
and the trace shows some noise from the power supply
http://forum.banggood.com/forum-topic-61279.html

   John

added picture of screen showing the noise on the trace -
not too bad considering its a 15 kit
Title: Re: Digital oscilloscope project/kit
Post by: PK on January 22, 2016, 07:40:19 PM
decided to assemble my DSO138 oscilloscope kit this afternoon
it worked first time even though the solder didn't flow that well on the surface mount components - an excuse to buy a smt work station I think ?
Heat and flux are the key, use plenty of both and avoid lead free solder.
Quote
and the trace shows some noise from the power supply
http://forum.banggood.com/forum-topic-61279.html
We keep a bag of 1000uF caps. Mostly for investigating these sorts of problems. But sometimes, on a one off job, they just get left in place.

Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 23, 2016, 04:08:35 AM
:D :D :D I've spent the afternoon assembling the component tester and it's case and it appears to work perfectly. :ddb: :ddb: :ddb: :ddb:

there weren't any  :zap: :zap: either.

trying to figure out the calibration was a bit of a bugger, there are online instructions but they aren't very clear...................or I'm thick :bang:
choose whichever you like.

Roy.


Nice one Roy  :thumbup:  , I added the three fly leads to mine which made calibrating easier  :zap: 



decided to assemble my DSO138 oscilloscope kit this afternoon
it worked first time even though the solder didn't flow that well on the surface mount components - an excuse to buy a smt work station I think ?

for now I've used the switches provided but may change them when I mount it in a box
modding is a must !

two things needs investigating
the variable capacitor C6 does not appear to do much
and the trace shows some noise from the power supply
http://forum.banggood.com/forum-topic-61279.html

   John

added picture of screen showing the noise on the trace -
not too bad considering its a 15 kit



Hi John ,

Some how I just knew you would find putting the DSO kit together to be a walk in the park  :thumbup:

do you think the noise problem is fixable ? 


Oh yes modding is a must lol , when you find a source of good quality switches could you post a link to them please  so I may purchase some replacements   :dremel: 




Cheers Rob 
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 23, 2016, 05:59:09 AM
Hi Rob.
this is mine in it's case.

  (http://i293.photobucket.com/albums/mm72/wheeltapper_2008/component%20tester_zpsu2ihwhef.jpg) (http://s293.photobucket.com/user/wheeltapper_2008/media/component%20tester_zpsu2ihwhef.jpg.html)

and here are the flyleads I modded on to a 3 pin header that plugs into the front socket.

(http://i293.photobucket.com/albums/mm72/wheeltapper_2008/component%20tester%20leads_zps9yirtok8.jpg) (http://s293.photobucket.com/user/wheeltapper_2008/media/component%20tester%20leads_zps9yirtok8.jpg.html)


Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 23, 2016, 06:18:02 AM
Hi Roy ,

That looks great  :thumbup:    ,methinks I should have maybe went for the one with the enclosure .


Cheers Rob
Title: Re: Digital oscilloscope project/kit
Post by: hopefuldave on January 23, 2016, 06:12:26 PM
You managed to chip off all the slag around those welded joints then Rob?  :lol:

Gotta admit, that seller does have quite a few good projects... :coffee: but I dont really need any more test gear......

Owon double beam digital scope with lcd display

2 x 30 v 3 A twin channel power supplies

Digital frequency counter

Lcd scope with frequency meter/ waveform generator

3 x UT 50 dvms etc etc.....

Aint got a bench big enough....or room for one   :lol:

Wot, no Spectrum Analyser? RF signal generator? Counter/Timer? GPIB controller?

What I *could* use at the moment is a decent / cheap LCR meter, I have to take stuff to work for one of the ladies to measure (overkill really, 6-digit precision...)

Dave H. (the other one)
Title: Re: Digital oscilloscope project/kit
Post by: PK on January 23, 2016, 09:17:34 PM
We have one of these at work http://www.peakelec.co.uk/acatalog/jz_lcr40.html
As I recall, it wasn't 'chinese cheap' but it works very well and we use it more than we thought we would.
Title: Re: Digital oscilloscope project/kit
Post by: awemawson on January 24, 2016, 03:06:25 AM
Yes I have one of those tucked away in a drawer. Extremely useful. Only irritation is that it's calibration period is obviously written into the firmware so it nags me to send it off whenever I use it!
Title: Re: Digital oscilloscope project/kit
Post by: John Swift on January 24, 2016, 10:03:53 AM
tried  the DSO138 power supply mod
with firmware 113-13801 -050 you don't get an improvement
unlike that as described at -
http://forum.banggood.com/forum-topic-61279.html
for the early version that's cloned using FW  113-13801-040

managed to buy 6 AA nicads for the Velleman K7105 'scope I built back in 2002
with no back light , the picture showing the trace of the test signal from the DSO138 is not great but shows the trace for comparison

     John

PS
RS Components do a slide switch that could be OK to mount onto a new front panel

 thought the 2 slide switches (sen1 & sen2)could be replaced by 1 rotary switch
but the rotary 4  pole 9 way switches I've found so far are several times more than the cost of the kit !
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 24, 2016, 10:35:37 AM
Hmmm...I guess what you pay for....

No point in buying a Mini if you want Ferrari performance... :Doh:
Title: Re: Digital oscilloscope project/kit
Post by: PekkaNF on January 24, 2016, 12:48:04 PM
I wonder how well this kind of rotary switches would work?
http://www.partco.biz/verkkokauppa/product_info.php?cPath=2065_1046_1276&products_id=15706&language=en

Are there any reasonable quality rotary switches like used on scope voltage input stage? Probably someone has considered building simple specialized input amplifiers, bit like differential amplifiers or such. Really hard to build an amplifier that is good in everything, but not too hard to build amplifier that does one or two things good eneough.

Pekka
Title: Re: Digital oscilloscope project/kit
Post by: John Swift on January 24, 2016, 01:58:54 PM
Hi Pekka

the switches look OK - I assume they are break before make

twice I have resorted to making a custom switch using parts from RS Components


http://uk.rs-online.com/web/p/rotary-switch-shaft-assemblies/0327894/
plus
http://uk.rs-online.com/web/p/rotary-switches/0352193/?origin=PSF_428206|acc
or
http://uk.rs-online.com/web/p/rotary-switches/0352222/?origin=PSF_428206|acc

  an expensive solution , but it worked

    John
Title: Re: Digital oscilloscope project/kit
Post by: PekkaNF on January 24, 2016, 03:24:46 PM
Those "Wafers" are not silly money, but shaft and rest of it will add up. But they are higher voltage and probably lower capasitance etc.

Pekka
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 28, 2016, 12:05:15 PM
Hi, just a quick pic of my test board.
(http://i293.photobucket.com/albums/mm72/wheeltapper_2008/test20board_zpshybj1zrh.jpg) (http://s293.photobucket.com/user/wheeltapper_2008/media/test20board_zpshybj1zrh.jpg.html)

it's not too bad, at least the LED works. :zap:

Roy.


My SMD kit arrived today ,,,,,,,,,,,,,,,,,,,,,,,,,,,,F*&k me  those are bloody small components Roy  :palm:

They are going to take some welding  , 3.2 mm  7018 rods should do the trick  :lol:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on January 28, 2016, 12:44:13 PM
Hi, just a quick pic of my test board.
(http://i293.photobucket.com/albums/mm72/wheeltapper_2008/test20board_zpshybj1zrh.jpg) (http://s293.photobucket.com/user/wheeltapper_2008/media/test20board_zpshybj1zrh.jpg.html)

it's not too bad, at least the LED works. :zap:

Roy.


My SMD kit arrived today ,,,,,,,,,,,,,,,,,,,,,,,,,,,,F*&k me  those are bloody small components Roy  :palm:

They are going to take some welding  , 3.2 mm  7018 rods should do the trick  :lol:


Rob

What about post weld heat treatment? Have you got a heat blanket to wrap the board in for stress relieving.....?? :lol: :lol:

Sounds like you are all having fun.... :dremel: :zap:  :beer:
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 28, 2016, 12:52:08 PM
 :lol: I was planning on peening the welds to relieve the stress John .


My Buck converter power supply arrived a few days back , opened it up and it has surface mount components  :palm:  , so a quick shop on Ebay fro some new gear ,

one has to buy new toys  :dremel:

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100831_zpsiquewa4e.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100831_zpsiquewa4e.jpg.html)


And some tackle to practice with .

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100832_zps4xyeegvs.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100832_zps4xyeegvs.jpg.html)


WTF !

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100829_zpscjm718mh.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100829_zpscjm718mh.jpg.html)

Rob




Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 28, 2016, 01:12:20 PM
Hi Rob.
yea, they are a bit titchy,  on that board the 0603 resistor is the smallest and that is what is on the scope kit, the frightening thing is,they come even smaller than that, at least three sizes.

funny coincidence, I just ordered an 858D hot air gun, different make to yours tho. got it off Fleabay.

If you are interested in a review see here.


 A different make again but the same thing.

make sure the chipping hammer is sharp before you start. :ddb: :ddb: :ddb: :ddb:

have fun.
Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 28, 2016, 01:26:45 PM
Hi Roy

Cheers for the youtube link  very interesting  :thumbup:  they all look very generic , my one  feels and look  canny , not bad for the money , mains lead is a tad short .

http://www.ebay.co.uk/itm/331330745304?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT




You say the resistors  come even smaller  :jaw:


I have put a fresh flap wheel on the grinder   :dremel:

Rob
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 28, 2016, 01:45:37 PM
I thought you'd like that, he has an SMD solder tutorial here.
&index=3

this is the hot air gun I ordered. http://www.ebay.co.uk/itm/371415508867?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

as far as I can see they all look the same.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 28, 2016, 02:14:53 PM
Nice one  Roy  :thumbup:

Question , How long  were you on soldering all those resistors ? 


and how do I know which way round the LED goes lol  :scratch:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 28, 2016, 02:41:03 PM
Rob, I think it took me about 15 mins per column.

put 3 volts across the led an see which way it lights.......................only 3volts tho or........ :zap: :zap: :zap: :zap: :zap: once its all done you can put 9 volts from pad to pad.

if you hold the board up to the light you can see the trace.

looking at mine there is a little green mark next to the negative side. YMMV :D

that guy has some very interesting videos.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on January 28, 2016, 04:01:54 PM
Hi Roy

Cheers for the LED tip /info  :thumbup:



Aye just been watching a few of Dave's videos , very interesting and he is quite a character  :clap: :clap:


Cheers Rob
Title: Re: Digital oscilloscope project/kit
Post by: kayzed1 on January 28, 2016, 07:36:06 PM
I have given up on mine now, i had the No trace on screen. I bought another screen kit and it is just the same...no trace but all other stuff is ok..just those two voltages that are not correct so binned it :doh: i went to the forum and one other person has asked the Q' with the same symptoms, and no answer from the mod or users, so bin it was.
Lyn.
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 29, 2016, 03:51:09 PM
Rob. I received my hot air station this morning.
you said your mains lead was short, how short is short?
mine is a separate one that plugs in the back and it's 5 foot long.

It works well tho, I tried desoldering a tiny 16 pin IC and it came straight off the board.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on January 29, 2016, 04:36:37 PM
Hi John, this is the one I got.
I ordered it on Tuesday and it arrived this morning.
http://www.ebay.co.uk/itm/371415508867?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT



Roy.
Title: Re: Digital oscilloscope project/kit
Post by: sparky961 on January 29, 2016, 07:23:25 PM
Boy, I'm kicking myself that I hadn't bought shares in this company when it was first brought to light.  I've lost count how many kits have reportedly been bought as a result!
Title: Re: Digital oscilloscope project/kit
Post by: PekkaNF on January 30, 2016, 02:20:29 AM
I got one scope kit yesterday.

I was just eyeballing the PCB. Should have a cunning plan for the external rigger signal, but I want to assemble it as "standard" now. Display comes over it, not too much space for connectors or standoffs.

There seems to be some "optional" connectors: Like Mini USB and some for programming. Anyone used them?
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on February 13, 2016, 08:25:09 AM
SNIP


My SMD kit arrived today ,,,,,,,,,,,,,,,,,,,,,,,,,,,,F*&k me  those are bloody small components Roy  :palm:

They are going to take some welding  , 3.2 mm  7018 rods should do the trick  :lol:


Rob
[/quote]

SNIP

Hi Rob.
We never heard how you got on with those SMD components.
You must have finished by now. :) :) :)

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on February 13, 2016, 08:45:01 AM
 :Doh:  Hi Roy ,

 I have had a wee practice using the hot air gun and solder paste with  mixed results  :(  , looking for a way to apply just the  correct amount of paste .

too much , wire feed a tad high  :lol:

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/16012819463511273474_zpscqezvyqz.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/16012819463511273474_zpscqezvyqz.jpg.html)

looking a bit better , placement is a bit wonky  :palm:

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/16012819494011458491_zpschkxzpua.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/16012819494011458491_zpschkxzpua.jpg.html)


I am using a stereo microscope to do the work , I think I need glasses  :palm:

(http://i1066.photobucket.com/albums/u410/RobWilson100/P1100836_zps57nyhnhp.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/P1100836_zps57nyhnhp.jpg.html)

I may practice a bit more this evening , things are a bit slow at  the moment as I am pulling my workshops to bits to make room for new machines  , like this wee beastie   :)

(http://i1066.photobucket.com/albums/u410/RobWilson100/Arboga%20Geared-head%20Drill/P1100838_zpsvzxoq4mb.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Arboga%20Geared-head%20Drill/P1100838_zpsvzxoq4mb.jpg.html)








Rob
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on February 13, 2016, 09:16:01 AM
You've got one upside down! all the pixies will fall out. :lol: :lol:

Nice looking drill press, is it a recon job or just chuck it in a space and use it?

posh microscope you have there,  :drool: all I've got is a MK1 eyeball and a magnifying glass. :bang: :bang:

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on February 13, 2016, 10:09:20 AM
So opinions please on the hot air rework unit ?

Are they good, rubbish or something else?

Nice effort Rob, half the trouble is placing the little blighters and getting them to stay put..... :Doh:

Then soldering them without dislodging.....
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on February 13, 2016, 01:23:34 PM
You've got one upside down! all the pixies will fall out. :lol: :lol:




BUGGER !  :lol: :lol:




Nice looking drill press, is it a recon job or just chuck it in a space and use it?



Roy.

It needs a wee bit TLC Roy , there is a crack in one casing , switchgear missing , two levers to make and fill in the whitless marks on the table ,nothing that I can't fix  but saying that it does work .  :dremel:

That there table is 500mm x 400mm ,it has an  8 speed 4MT power feed quill  , not a bad swap for my RF25 mill drill . 


Rob
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on February 13, 2016, 01:27:56 PM
So opinions please on the hot air rework unit ?

Are they good, rubbish or something else?

Nice effort Rob, half the trouble is placing the little blighters and getting them to stay put..... :Doh:

Then soldering them without dislodging.....


Cheers Mate  :beer:

The hot air rework station seems fine to me John , but what would I know  :lol:  , does the job , can't complain for the money  :thumbup:

I just need more practice  :palm:



Rob
Title: Re: Digital oscilloscope project/kit
Post by: awemawson on February 13, 2016, 02:21:00 PM
Can you not make a thing like the weighted pointer that I use for silver soldering - stand with long pointed bar pivoted and weighted to rest on the work and stop it blowing away in the flame - or in your case hot air gun ?
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on February 13, 2016, 03:35:53 PM
Or you could just hold them with a pair of tweezers. :ddb:

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: awemawson on February 13, 2016, 04:07:40 PM
It's all to do with gaining an extra hand - tweezers use one up  :lol:
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on February 13, 2016, 05:51:34 PM
How many do you need? One holds the tweezers, one holds the iron / air gun.
if you are using an iron you pre-solder one pad, then hold the component in place and reflow the solder, then do the other end with solder.

With a hot air gun you use solder paste.

simples.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: PK on February 14, 2016, 07:23:44 AM
 A deft hand on an iron is better for assembly, but hot air is essential if you are ever going to remove a chip with more than two solder pads.
PK
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on February 14, 2016, 07:28:33 AM
Very true.
I managed to remove a 16 pin chip from an old board, no trouble.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: awemawson on February 14, 2016, 08:11:57 AM
I've done that with  16 pin surface mounts using a 50 watt Weller TC iron using low meting point solder 'additions' to keep it fluid long enough. Flood the leads with low melt solder, remove the chip with a cocktail stick, clean up with solder wick.

Back in the early days of 7400 series logic - all through hole of course - I used to salvage chips off boards by the simple expedient of putting a 14 or 16 pin i/c inserter clip on the victim, and flashing the back of the board with a blow lamp while pulling on the clip. Not recommended if you want to reuse the board though with care surprisingly little damage was done. The occasional plated through hole would come as well leaving the chip looking as though it was wearing trousers  :lol:
Title: Re: Digital oscilloscope project/kit
Post by: hopefuldave on February 14, 2016, 08:31:45 AM
Sounds like the IC "reclaimer" I saw who turned a blowlamp on the solder side then bashed the boards on the bench - 95% removal rate, and they *looked* fine...

Dave H. (the other one)
Title: Re: Digital oscilloscope project/kit
Post by: DICKEYBIRD on February 14, 2016, 09:51:06 AM
Just a quick post to say thank you very much to all who have contributed to this thread.  I read & enjoyed every word.  I never knew so many wonderful things are done by mere mortals in their own homes & workshops....with so little money!

Cheers to you one & all! :beer:
Title: Re: Digital oscilloscope project/kit
Post by: Pete W. on February 16, 2016, 02:22:42 PM
Sounds like the IC "reclaimer" I saw who turned a blowlamp on the solder side then bashed the boards on the bench - 95% removal rate, and they *looked* fine...

Dave H. (the other one)

Maybe I'm about to propound yet another urban myth but here goes anyway:   :lol:   :ddb:   :lol:   :ddb:   :lol:   :ddb: 

My understanding is that the flame (e.g. propane or paraffin) is a plasma so it's conductive.  There's little risk of electrostatic discharge damage  :zap:  to the chips because, while they're in the flame, all their 'legs' are effectively shorted together. 
Title: Re: Digital oscilloscope project/kit
Post by: awemawson on February 16, 2016, 02:40:47 PM
Well certainly I don't remember any of the ic's being faulty after removal that way, and some were the early MOS memory chips that had little inbuilt by way of electrostatic protection. But it was mainly TTL 7400 series or the Mullard  FCHXXX or FCKXXX series equivalents.

Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on February 26, 2016, 02:50:44 PM
 Evening Chaps  :wave:


I thought I would mess about with anouthe Bangood project tonight  :zap: , I welded up the wee power supply to use with the signal generator .

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100937_zpsqa1vqdds.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100937_zpsqa1vqdds.jpg.html)

Not a bad board it dose have a few SMD parts , three fairly large inductors , noting the new hot air gun could not cope with  :thumbup:


(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100939_zps0wkq5zcq.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100939_zps0wkq5zcq.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100941_zps54nfdm4m.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100941_zps54nfdm4m.jpg.html)

The soldering welding is not the best a my solder paste had gone off  :( anyway I got the project  up and running with only one hitch  :Doh: , some fool soldered one of the shottky diodes arse about tit .
Which causing the board to have no minus voltage  outputs  ,,,,,,,,,,,,,,,,,and made the buck convertor get a tad warm  :palm:

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100944_zps6t3vf7ds.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100944_zps6t3vf7ds.jpg.html)

I must admit to enjoying troubleshooting my f45k ups  :lol: and here are a few action shots  of it and the signal generator working  :ddb:

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100948_zps2fvaogs1.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100948_zps2fvaogs1.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100949_zpsrsmomaky.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100949_zpsrsmomaky.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100950_zpshpo6cipb.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100950_zpshpo6cipb.jpg.html)

all gipping stuff lol .


Question for the more knowledgeable , the board has a 3.3v output  , I would rather have a 9v out put , is there a replacement for the 1117-3,3  smd voltage regulator that I can replace with a 9v reg ?

I have had no luck finding one ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,due to not knowing what I am looking for  :lol: :lol:


Cheers Rob   

 

 
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on February 26, 2016, 03:26:02 PM
Rob,
You may need to mod the board to get 9 v.....

Have you got a link to the kit or the schematic?
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on February 26, 2016, 03:44:02 PM
Hi John ,    I can't find a circuit diagram for this project  , I was just hoping that there was a 9v Reg in the same package I could just solder in place .



But I am  always up for madmodding lol


Rob
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on February 26, 2016, 04:07:39 PM
Rob,
What about a link to the kit you bought?

The little 3.3v regulator wont have enough juice applied to it to get 9v out...that is, the 3v reg will only have about 6v in to it to reduce its dissipation....so a drop in wont work
You may have to cobble something using the 12 v side.....
Title: Re: Digital oscilloscope project/kit
Post by: John Swift on February 26, 2016, 04:18:34 PM
Hi Rob

in the advert they say they don't provide a schematic !!! - no good for modders  :lol:

I guess the switching power supply generates some thing like plus and minus 18V

the positive SMP output  supplies the 78M12 and 78M05 regulators for the  +12V and +5V outputs
and the negative SMP supplies the 79M12 and 79M05 regulators for the -12V and - 5V outputs

the "1117"  3.3V regulator looks like is powered by the +5V regulator (78M05)

to add a 9V regulator you need to either tap into the supply to the 12V regulator or the 12V output

the 9V regulator can be a 78M09 or a LM317 adjustable regulator and resistors

     John
  PS

Do you had a photo showing the PCB tracks of the other side of the board
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on February 26, 2016, 04:26:23 PM
Hi Rob.
I'm still waiting for my power supply kit to arrive, it was allegedly posted on the 30 Jan so where is it  :bang: :bang: :bang: :bang:

I've got the sig gen kit but I want to get the supply running before I build it or it will sit there and annoy me.

I built the frequency counter kit and that works OK ( even tho I said I wasn't going to get it ) :doh:

I'm also thinking of getting this http://www.banggood.com/DIY-Aviation-Band-Receiver-Kit-High-Sensitivity-p-990306.html as I live near Norwich airport.

could someone look at the schematic of this receiver and tell me if I could connect the frequency counter to it to check the receiving frequency.
cheers
Roy.
Title: Re: Digital oscilloscope project/kit
Post by: John Swift on February 26, 2016, 04:57:49 PM
Hi Wheeltapper

 you need a frequency counter that the   displayed frequency can be off set by 10.7MHz
this avoids having do  the maths to work out what its tuned to

looking at the circuit the coil L6 , capacitor C14 and varicap diode D1  set the frequency of the local oscillator (part of U1) - this is what needs to be the input to the counter

the output of the oscillator is mixed with the signal you want to receive
the difference between the two has to be 10.7MHz to pass through 10MHz filter  fil1
and when amplified by Q1 and U2 pass through the IF transformer T1

D1 is the AM detector that resolves the audio signal to be amplified to drive the loud speaker or headphones

       john

PS

a frequency display like this -
http://www.ebay.co.uk/itm/50MHz-LCD-Frequency-Counter-Module-with-IF-Offset-Free-UK-Postage-/172103761140?hash=item28122efcf4:g:mKAAAOxyThVTXnoD

Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on February 26, 2016, 05:22:24 PM
Thanks John but I've just realised that it won't work anyway.
The receiver tunes from 118 mhz to 136mhz and the frequency meter goes from 1mhz to 50 mhz.  OOPS. :bang:

Oh well, back to he drawing board.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on February 26, 2016, 05:26:27 PM
You could always add a prescaler to the counter....

But that adds to the complexity of things.....
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on February 27, 2016, 05:27:26 AM
Cheers for the replies John R and John S  :thumbup:

I will look for a similar usb to 9v PSU  project  or maybe something to be powered from the 12v  supply on the board  :zap:


Hi Rob.
I'm still waiting for my power supply kit to arrive, it was allegedly posted on the 30 Jan so where is it  :bang: :bang: :bang: :bang:


Roy.


Hi Roy , I have had delivery times ranging from one week to 6 weeks  :Doh:  , it's a bit pot luck ,,,,,,,,,,,,,,,,,,,,,ooooh just remembered you do know things go a bit tits up in China for a fortnight this time of year , well the time you placed the order , its their NEW YEAR ! :ddb:  :beer: :ddb:


 :lol: :lol: so you gave in and got the frequency counter  :clap: :clap: nice one  , well its your turn to lead me astray  :palm:

I live on the centre line for Newcastle airport so I have just ordered that Aviation band receiver  :thumbup:


Cheers Rob


 
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on February 27, 2016, 08:36:08 AM
Oh dear, naughty me  :) :D :) :D

I haven't ordered mine yet, now I might wait until you build your's to see if it's any good. :lol: :lol: :lol: :lol:

Are we having fun yet? :clap: :clap:

cheers
Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on March 05, 2016, 04:31:58 AM

Are we having fun yet? :clap: :clap:



Wey aye  :thumbup:


Has your PSU kit shown up Roy ? 




I put the 0-30v PSU kit together last night  :zap:

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100952_zpsrjqwrxtb.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100952_zpsrjqwrxtb.jpg.html)


I added the 12v cooling fan , there is a 24v output for a fan provided , I just swapped the voltage reg for a 12 v one I had .

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100956_zpsxietznrq.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100956_zpsxietznrq.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100957_zpsjq1tmfns.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100957_zpsjq1tmfns.jpg.html)

All is good , no magic smoke  escaping  :)

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100955_zps90t3qbf5.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100955_zps90t3qbf5.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100954_zpsnyk0mvuw.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100954_zpsnyk0mvuw.jpg.html)



NEXT !  :D




Cheers Rob
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on March 05, 2016, 07:10:18 AM
No sign of it yet Rob, :scratch: talk about a slow boat to from China.

I suppose it'll get here when it gets here.

I've been amusing myself repairing things here, my freeview satellite box locked up, checked it out, bad power supply caps.
then the freeview/ hard drive recorder locked up as well, reason, bad bloody caps again.

both working now,I feel quite chuffed about that.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: PekkaNF on March 06, 2016, 12:32:34 PM
Joined the club Today. Assembly was pretty straightforward. Only inconveniece was that all slide switches had most of the pins wonky.

I haven't calibrated it yet, just checked that it works, shows the signal and all slide switch positions are registered.

Pekka
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on March 06, 2016, 12:37:05 PM
Joined the club Today. Assembly was pretty straightforward. Only inconveniece was that all slide switches had most of the pins wonky.

I haven't calibrated it yet, just checked that it works, shows the signal and all slide switch positions are registered.

Pekka

Nice one Pekka  :thumbup:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on March 06, 2016, 01:13:22 PM
Yay Pekka, welcome to the nuthouse club.  :D :D

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: PekkaNF on March 07, 2016, 12:10:13 AM
Thanks. I was surpriced that it worked on first try. I was mentally prepared for troubleshootting.

I sill have to find instructions on how to calibrate it and then I'll feed in signl from the signal generator and see how the amplifier works. Time to refresh my memories from electronics.

Pekka
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on March 07, 2016, 07:58:17 AM
Did you get the kit with the SMD components already fitted or not?

If not, did you have fun fitting them? :lol:

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: PekkaNF on March 07, 2016, 08:04:33 AM
Noooooooo...I'm noob....

I ordered the kit with all SMD-parts fitted. I have touched just a few SMD-parts and my confidence is not high. Therefore my myriad questions around SMD fluxes/pastes/irons.....

But it is a fun part I can not avoid in future :palm:

Pekka
Title: Re: Digital oscilloscope project/kit
Post by: John Stevenson on March 15, 2016, 06:51:59 AM
OK, I cheated and bought a pre built one.
This way it will at least work and not adorn the bench for 10 years before getting thrown in the bin.

Seen a box on thingiverse to stick it all in and I'll 3D print one this week.

Only problem I have at the moment is how do I use the thing ?

Bought it for looking at the opto output on an encoder to make sure I get nice square waves and to adjust Channel A and Channel B to be spaced by 90 or 180 or whatever.
This is on a home made disk encoder and not a sealed unit which will be accurate as sent from the factory.

I also have a 'proper' 'scope but it has that many knobs and bells on it that even ower dog can't understand it and he's got an IQ 6 up from mine.
Title: Re: Digital oscilloscope project/kit
Post by: PekkaNF on March 18, 2016, 02:54:10 PM
MBE deservs better answer, since I'm not sure if I understood question right....

Anyways, such a little detail never stopped me.

If I understand it right, you have a DIY quadrature encoder that has two channels with 90 degree phase difference and 50% duty cycle each. Normally these outputs are marked A and B. Both produce sguare wave.

Challenge is to adjust opto/HAL/whatever couplers mechanically to a correct position to produce 90 degree phase difference?

Here, for demostration purposes I adjusted signal generator to simulate those signals CH1/CH2, same wave form, same duty cycle, 90 degrees phase difference, the real scope on background shows this.

If you connect either encoder outputs (A/B) against the ground to this one channel scope you should get nearly identical signals. Both channels in isolation should produce "perfect" square wave. Only thing is, that probably mechanics is not accurate enough to produce nearly ideal 50% duty cycle i.e. ON and OFF state signals should be of same length, but probably are not. I does not matter in the end if you use only rising OR falling edges of the signal (i.e. twice the one cahnnel resolution, not 4x), but the signal "looks a little funky".

If you connect your single channel scope between hot wires of A and B channels, you'll get interesting signal, that should allow you to adjust (mechanically?) nice symmetry for the signals. This should look like the signal on this toyscope on front on my attached picture here.

When you connect the scope input between A and B signal wires, you'll get the product of these signals and the product should look symmetrical. Since you are adding two identical signals that have a 90 degree phase shift. A little "tweak" will show very nicely on the signal and since human eye detects change easily, that sort of signal will produce pretty good adjustment accuracy.

The signals could be added with a resistor network or such and utilize the the signal form factor, but then signals should be pretty stable to start with.

Was any of this anything you asked?

I find the old school analog scope easier to use. From the panel you see all adjustments on one go and nothing is hidden in the annals of menus....Of course DSO:s normally have the magical button that will find tha signal and display it....but then I'll spend some time trying to figure what settings are those numbers on the screen.

Pekka
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on April 01, 2016, 05:44:33 PM
Hi Rob, did you ever get that airband receiver kit?
I finally received the psu for the frequency generator Wednesday. I waited and waited then got in touch with Banggood and they sent a replacement by airmail.

I assembled it this afternoon and it works a treat, now to build the freq gen kit.

cheers
Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on April 02, 2016, 06:54:27 AM
Hi Roy

Yes , the Air band receiver kit arrived a couple of weeks back .

 (http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100965_zpsgblrsb3k.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100965_zpsgblrsb3k.jpg.html)

I just have not had time to weld it together , much upheaval in my shop  :(


I had a package go AWOL and they were sharp to get a replacement sent out   , glad you got sorted wit your PSU kit  :thumbup: 


anyway  :worthless:  ,,,,,,,,,,,,,, :lol:



Rob
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on April 02, 2016, 07:44:06 AM
Oh all right then :)

(http://i293.photobucket.com/albums/mm72/wheeltapper_2008/power%20supply_zpsam1jvy2p.jpg) (http://s293.photobucket.com/user/wheeltapper_2008/media/power%20supply_zpsam1jvy2p.jpg.html)

mustn't break the rules.  :mmr:

cheers.
Roy.

Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on April 02, 2016, 07:54:12 AM
Nice one Roy  :thumbup:

What did you use to solder on the inductors and what's your plans for the signal generator ? 


I was recommended a book on electronics last week " The art of electronics P Horowitz , W Hill "  very informative and well worth the money  :coffee:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on April 02, 2016, 08:02:06 AM
Those who have one of these wee DSO may be interested in this case .

http://www.banggood.com/Transparent-Acrylic-Sheet-Housing-Case-For-DSO138-Oscilloscope-p-1034768.html


Rob
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on April 02, 2016, 08:21:53 AM
Nice one Roy  :thumbup:

What did you use to solder on the inductors and what's your plans for the signal generator ? 


I was recommended a book on electronics last week " The art of electronics P Horowitz , W Hill "  very informative and well worth the money  :coffee:


Rob

Hi.
(1)I assembled the whole thing with my soldering station using a 1.6 mm tip set at 350c.

(2) don't know yet.  :lol: :lol:

Roy.

Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on April 02, 2016, 08:24:56 AM
Those who have one of these wee DSO may be interested in this case .

http://www.banggood.com/Transparent-Acrylic-Sheet-Housing-Case-For-DSO138-Oscilloscope-p-1034768.html


Rob

Like it, ordered it, sending you the bill  :lol: :lol: :lol: :lol:

seriously, I always thought it was very vulnerable as it is and I wondered why they didn't have a case.
it must be a new thing.
cheers
Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on April 02, 2016, 08:27:19 AM
 :lol: :lol: :lol:  Cheers Roy ,I hope you stuck two on my tab , one for me  :thumbup:   

Quote
(2) don't know yet.  :lol: :lol:

Always a good plan  :lol:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on April 02, 2016, 09:27:05 AM
My theory is, if you don't have a plan then you can't moan when it doesn't work out. :D

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on April 02, 2016, 10:12:41 AM
My theory is, if you don't have a plan then you can't moan when it doesn't work out. :D

Roy.


 :lol: :lol: :lol: :lol: :lol: :lol:   :med:
Title: Re: Digital oscilloscope project/kit
Post by: hermetic on April 02, 2016, 12:47:43 PM
The plan is "There is no plan", that's the plan! (Marx Brothers)
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on April 02, 2016, 01:27:17 PM
Well, whadda know. I just assembled the frequency generator kit and the darn thing worked. no  :zap: :zap: :zap:

I won't bother posting a pic of it working because it'll look just like Robs pic.

That's 5 for 5.


It'll all end in tears, I can see it coming. :zap: :zap: :zap: :zap: :zap: :zap:

cheers for now.
Roy.

PS, Rob hurry up and build your receiver so I can waste spend some more money. :lol: :lol: :lol:
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on April 02, 2016, 03:25:07 PM


PS, Rob hurry up and build your receiver so I can waste spend some more money. :lol: :lol: :lol:

I have been trying to put the kit together for a week Roy , hopeful I may have some free time tomorrow  :zap:


5 for 5   :clap: :clap: I put one of the diodes backwards on my PSU  :Doh:



Rob 


Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on April 02, 2016, 04:00:22 PM
I didn't even realise they were diodes until I read someone on the Banggood forum who put them in back asswards.
I thought they were resistors. It took a lot of looking to see the white line.

Blind as well as daft. :doh: :doh:
At least I read that BEFORE I fitted them. :bow:

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on April 02, 2016, 04:08:31 PM
 :lol: :lol: Aye they be Schottky diode ,,,,,,,,,,,,and guess which twat fit one arse about face  :palm: 

But I did trace where I Had made the mistake  :zap:


Rob 


PS , I see your local airport is very close Roy
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on April 02, 2016, 05:38:43 PM
Yes, Norwich International is about a mile away. the main runway is parallel to the back of our house.
luckily, although it's an international airport it's not that busy so it doesn't disturb us much.

the prevailing wind ensures that mostly they are landing when they pass us so it's not that noisy. what does drive us nuts are the damn helicopters, we've got police, air ambulance and one serving the oil rigs and they come in from any old direction.

the upside is, every time the Red Arrows do a show on the east coast they use Norwich as a staging airport and when they come in they fly across our house at low level before landing so we get a free show.

swings and roundabouts I suppose.

Roy.

Title: Re: Digital oscilloscope project/kit
Post by: DMIOM on April 03, 2016, 04:10:34 PM
O/T re digital scope but these may be workshop-useful, has any tried one?

   http://www.banggood.com/Low-ZVS-12-48V-20A-1000W-High-Frequency-Induction-Heating-Machine-Module-p-1038472.html

Definite scope for  :zap:

Dave
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on April 03, 2016, 04:39:38 PM
 :lol: Funny you should mention it Dave I bought the smaller one and promptly fryed  it  :zap:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: seadog on April 03, 2016, 04:43:05 PM
Damn, I bought this a few days ago to play with - www.banggood.com/5V-12V-ZVS-Induction-Heating-Power-Supply-Module-With-Coil-p-1015637.html
I wish I'd seen the other one  :doh:
Title: Re: Digital oscilloscope project/kit
Post by: kayzed1 on April 03, 2016, 04:52:58 PM
I have that one sat on the shelf, bit of a wimp so not plugged it in yet...just hope it does not go  :zap:
Lyn.
Title: Re: Digital oscilloscope project/kit
Post by: Will_D on April 04, 2016, 05:01:44 AM
What don't they sell!

Looks like Banggood is the mad-modders ultimate toy shop!

I am having to sit on my hands when reading these threads!
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on April 04, 2016, 06:05:03 AM
:lol: Funny you should mention it Dave I bought the smaller one and promptly fryed  it  :zap:


Rob

Whats broken on it Rob? I'm surecwe can fix it.... :dremel:
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on April 04, 2016, 02:17:25 PM
:lol: Funny you should mention it Dave I bought the smaller one and promptly fryed  it  :zap:


Rob

Whats broken on it Rob? I'm surecwe can fix it.... :dremel:



Sure mate , shall I stick it in the post  :lol:

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100966_zpsjtcvvevd.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100966_zpsjtcvvevd.jpg.html)


As you can see Bob has been at it  :)  , I now have all the toys to desolder stuff ,,,,,,,,,,,,,,,,,sort of all the gear ,no idea  :lol:

Smoke was emanating from between the two inductors .

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/2016012914065194-1015637_zpsw7wno0ik.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/2016012914065194-1015637_zpsw7wno0ik.jpg.html)


So to see whats what you have to remove the two capacitors from underneath .

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100978_zpsmxcg3ono.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100978_zpsmxcg3ono.jpg.html)

To remove the inductors ,

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100977_zpsuewvsdki.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100977_zpsuewvsdki.jpg.html)

To get to the things that have had the ID scrubbed , for F*&k sake it a friggin toy , why!   :bang:

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100971_zps3obzl3yg.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100971_zps3obzl3yg.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100970_zpsj7glxted.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100970_zpsj7glxted.jpg.html)

These turned out to be N channel MOSFET,s

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100972_zps4nloktqc.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100972_zps4nloktqc.jpg.html)

The diodes test OK

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100974_zps41rezo1v.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100974_zps41rezo1v.jpg.html)
(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100975_zpsgjoaha3i.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100975_zpsgjoaha3i.jpg.html)
 

As do the resistors

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1100976_zps2i3jlnv1.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1100976_zps2i3jlnv1.jpg.html)

So can the magic smoke be released and the heater stop working , then the parts test ok under no load ? 

It died due to some tit not limiting  the max current on his bench PSU   :zap:

So that's the project , just build it bigger  :thumbup:


Rob




Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on April 23, 2016, 08:19:18 AM
Hi people.
for those of you who have the scope kit I just received and fitted the plastic case kit and I have a few tips for you.

first thing is the LED at the bottom of the main board, this needs to be flush with the board or it will be squashed.
then, after the display part of the case is done and you fit the main board, there are 4 nuts to hold the board in place, DON'T tighten these up too much or the switches lock up. what I did was to run the nuts up so they touch the board then put locknuts on and lock them together.

this holds the board in place and also, the locknut comes flush with the side pieces of the case so when the back piece is fitted the rear nuts can tighten up without bending the plastic.

the only annoying thing is, at the top r/h side of the board is a two pin connector for the power supply, they forgot to leave a cutout in the case for this so it's inaccessible.

other than that it certainly protects the board and screen so I'm quite happy with it.


PS
by the way Rob, I seem to have accidentally ordered the airband receiver  :Doh: :Doh: I can't understand how that could have happened. :) :lol: :lol: :D

have fun guys.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on May 02, 2016, 12:14:02 PM



PS
by the way Rob, I seem to have accidentally ordered the airband receiver  :Doh: :Doh: I can't understand how that could have happened. :) :lol: :lol: :D

have fun guys.

Roy.


 :lol: :lol: Aye it happens Roy    :thumbup:   , I still have to put my kit  together  :zap:  , So is it worth getting the plastic case for the DSO ? 

Rob

Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on May 02, 2016, 02:00:49 PM
Hi Rob and welcome back.

yes, I think it's worth while, it protects the screen if nothing else.

I put my radio together yesterday and guess what, the damn thing doesn't work and one of the transistors seems to be getting rather warm.

Time to use all the skills I haven't got to try to fix it  :doh:

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on May 02, 2016, 02:11:48 PM
Cheers Roy


Oh !  any ideas whats wrong with it Roy ?   , I will hang fire with my kit until you find out what's up with yours  :zap:



Rob

PS , I was expecting to see snow on the hills around Edinburgh when we came into land  :loco: 
Title: Re: Digital oscilloscope project/kit
Post by: shipto on May 02, 2016, 03:10:39 PM
I reckon we should get a madmodder discount considering how much we are all spending there.
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on May 02, 2016, 03:24:49 PM
Rob,
I haven't got a clue as yet.
I have to be in the right frame of mind to start trying to figure it out.

or I could send it to you to fix. :lol: :lol: :lol: :lol:

It's really annoying that of all these kits this is one I could use and it's bust.

ho hum.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on May 02, 2016, 04:27:41 PM
Roy,
Which tranny is getting warm?

Have you checked you got the components in the right way round? :zap:
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on May 02, 2016, 05:19:51 PM
one of the transistors seems to be getting rather warm.

Just write EF91 on it and call it a valve ... it'll be fine then ...  :zap:

Dave
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on May 02, 2016, 05:36:03 PM
It's the one designated U1 on board.
it's a 78LO8. same edge of the board as the BNC socket between two caps.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: nrml on May 02, 2016, 05:39:29 PM
After following this thread from the beginning, I have finally succumbed and gone and ordered the oscilloscope and transistor tester kits (with case). I have no idea how to use an oscilloscope and I have only ever soldered one small PCB before in my life. Such trivial details are not significant are they :scratch:? And to make matters worse I've ordered the version that needs SMD components soldering :doh:.

Mr Wilson - you are a bad influence :poke:. Giving people like me ideas above their station. Whatever next?
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on May 02, 2016, 06:04:18 PM
After following this thread from the beginning, I have finally succumbed and gone and ordered the oscilloscope and transistor tester kits (with case). I have no idea how to use an oscilloscope and I have only ever soldered one small PCB before in my life. Such trivial details are not significant are they :scratch:? And to make matters worse I've ordered the version that needs SMD components soldering :doh:.

Mr Wilson - you are a bad influence :poke:. Giving people like me ideas above their station. Whatever next?


SMD components eh. good luck with that. :lol: :lol: :lol: :lol:
If you've never used them before I suggest you get a test board as mentioned in a previous post, the're cheap enough to screw up  mutilate construct and give some practice.

here's one, http://www.ebay.co.uk/itm/DIY-Kit-SMT-SMD-Component-Welding-Practice-Board-Soldering-Practice-UK-seller-/351548500382?hash=item51d9ec699e:g:V~MAAOSwT6pV36QW

It's all fun I tell you, well that's what they told me anyway. :)

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on May 03, 2016, 01:59:10 AM
It's the one designated U1 on board.
it's a 78LO8. same edge of the board as the BNC socket between two caps.

Roy.

Little 8V 100mA voltage regulator .. Maybe a short cct. somewhere else on the board ??

They also get damned hot as do most regulator chips if you get them reverse connected.  :(

Dave

http://uk.farnell.com/on-semiconductor/mc78l08acpg/ic-linear-voltage-regulator/dp/1652346
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on May 03, 2016, 02:36:29 PM
After following this thread from the beginning, I have finally succumbed and gone and ordered the oscilloscope and transistor tester kits (with case). I have no idea how to use an oscilloscope and I have only ever soldered one small PCB before in my life. Such trivial details are not significant are they :scratch:? And to make matters worse I've ordered the version that needs SMD components soldering :doh:.

Mr Wilson - you are a bad influence :poke:. Giving people like me ideas above their station. Whatever next?


 :lol: :lol: :lol: Good on ya  nmrl  :thumbup:     

I am all brand new to this electronics lark myself , hardly used a soldering iron until I had started this thread  :dremel: 


Rob


PS remember no photos it did not happen  :poke:


Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on May 03, 2016, 02:38:24 PM
Rob,
I haven't got a clue as yet.
I have to be in the right frame of mind to start trying to figure it out.

or I could send it to you to fix. :lol: :lol: :lol: :lol:

It's really annoying that of all these kits this is one I could use and it's bust.

ho hum.

Roy.



Me fix it Roy  :lol:   I can desolder it for you  :dremel:   



I am dam sure the more enlightened will work the problem out  :smart:



Rob
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on May 03, 2016, 02:54:35 PM
I reckon we should get a madmodder discount considering how much we are all spending there.


Aye should we  :med:  I got into work this morning to find  a wee Banggood order has arrived while I was on holiday . 

(http://i1066.photobucket.com/albums/u410/RobWilson100/Electronics%20Projects/P1110511_zpsdplpqgi7.jpg) (http://s1066.photobucket.com/user/RobWilson100/media/Electronics%20Projects/P1110511_zpsdplpqgi7.jpg.html)

Rob
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on May 03, 2016, 03:00:16 PM
OFM.....what you been buying Rob?...

You should stop going on holiday...
I would have visited this w/e but you be out.....lol
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on May 03, 2016, 03:01:26 PM
Ok lads

A question for the electronics chaps ,   I would like to build a circuit that would charge up a bank of capacitors to anywhere between say  10v  to  35v and when charged  to the set voltage disconnect the power supply from the capacitor bank .   

Any pointers ?   :scratch:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on May 03, 2016, 03:05:45 PM
OFM.....what you been buying Rob?...

You should stop going on holiday...
I would have visited this w/e but you be out.....lol

Just stocking up on a few bits mate  :thumbup:    , capacitors ,transistors, trimmer pots  ,perf board ,wee switches ands a peltier junction to play with ,  every project I look at I need parts  :bang:


Where you at your daughter's over the weekend ?

 
Rob
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on May 03, 2016, 03:39:25 PM
OFM.....what you been buying Rob?...

You should stop going on holiday...
I would have visited this w/e but you be out.....lol


Where you at your daughter's over the weekend ?
 
Rob

Yup, visiting yet again....the boys are growing bigger.... I think they'll turn out to be tuff geordies..lol... :lol:
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on May 03, 2016, 03:42:13 PM
True Geordies as well John  :thumbup:

Good to hear they are doing well  :clap: :clap: , maybe next time you're up mate   :beer:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on May 03, 2016, 04:00:36 PM
Ok lads

A question for the electronics chaps ,   I would like to build a circuit that would charge up a bank of capacitors to anywhere between say  10v  to  35v and when charged  to the set voltage disconnect the power supply from the capacitor bank .   

Any pointers ?   :scratch:


Rob

Nope, no Pointers, mates got a Staffy  :lol:

Depends on what you want to do, I'd use a PIC, one analogue channel to read a pot, and set the reqd. voltage and another to read the cap. bank volts.

Use one digital channel to drive a relay to disconnect when it's up to what you want.

How big is this cap. bank anyway ??  Not a good idea to try to charge a damn great heap of the things from zero without some attempt at a current limiter. A big cap. is close to a short circuit at initial switch on ...  :zap:
Stresses the rectifier no end ...

You going to Doncaster BTW ???

Dave

Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on May 03, 2016, 04:07:49 PM


You going to Doncaster BTW ???

Dave


 :lol: :lol: :lol: :lol:

Hi Dave , whats on at Donny ?  will there be bacon or sausage  butties involved  ?  :D

Micro controlled , mmmmmmm sounds like a plan  :thumbup: 

I was planning  to use a current limiting resistor to charge the caps .  As to the size of the cap bank thats still a big question mark  :palm: , I would like to build a small cap discharge spot welder 
:zap:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on May 03, 2016, 04:12:18 PM
Harrogate Show is at Doncaster this year, nowt to stop you taking your own bacon / sausage butties if you want. 

Or even a Hog Roast if you're that peckish ...  :clap:

Dave
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on May 03, 2016, 04:19:53 PM
 :lol: Hog roast would fit in the van Dave  :lol:

I will look into it , are you going mate ?


Rob
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on May 03, 2016, 04:29:08 PM
If you know the current the welder takes and for how long it takes it a first approximation would be:

Say ... 50A for 0.2 seconds ...

I x T = 1/2 ( C x V2 )

So: Assume 50A for 0.2 seconds and an applied voltage of 35V

C = ( 2 ( I x T )) / V2

Which I make about 16 and a bit mF  or 16,500 uF

This does assume the cap. voltage stays at 35V all the time which it won't ...  :(

No real idea what current a spot welder takes or for how long?

Don't they have some sort of timer to gate the current ?? Another easy job for a PIC ...  :beer:

Dave
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on May 03, 2016, 04:30:45 PM
:lol: Hog roast would fit in the van Dave  :lol:

I will look into it , are you going mate ?


Rob

Yup, got my ticket   ... Codgers Discount rate ...  :thumbup:

Saturday probably ... about 90% certain.

D.
Title: Re: Digital oscilloscope project/kit
Post by: Bluechip on May 03, 2016, 04:46:31 PM
Have you got a diagram of what you want to build ... ?

Not having any real idea of how these things work, it seems to me to use a thyristor as the switching element as these turn off anyway when the current drops below the holding value and it wont switch on again until another gate pulse arrives ...  :scratch:

D.
Title: Re: Digital oscilloscope project/kit
Post by: PK on May 03, 2016, 04:49:12 PM
Ok lads

A question for the electronics chaps ,   I would like to build a circuit that would charge up a bank of capacitors to anywhere between say  10v  to  35v and when charged  to the set voltage disconnect the power supply from the capacitor bank .   

Any pointers ?   :scratch:


Rob

The details depend on things like how: how big the caps are, how fast you want to charge them, and what your input voltage to this circuit will be.

But essentially you would use a current limited power supply set to the target voltage and a diode. Very simple for small (ie <=10A) currents.
PK
Title: Re: Digital oscilloscope project/kit
Post by: awemawson on May 03, 2016, 04:51:54 PM

[/quote]


 :lol: :lol: :lol: :lol:

Hi Dave , whats on at Donny ?  will there be bacon or sausage  butties involved  ?  :D

Micro controlled , mmmmmmm sounds like a plan  :thumbup: 

I was planning  to use a current limiting resistor to charge the caps .  As to the size of the cap bank thats still a big question mark  :palm: , I would like to build a small cap discharge spot welder 
:zap:


Rob
[/quote]

Rob,

My stud welder has 200v caps of 66,000 microfarad, that charges up to a max of about 180 volt and will fix an M6 stud as per this thread (no pun intended !):

http://madmodder.net/index.php/topic,10358.0/all.html
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on May 04, 2016, 01:55:28 PM
Cheers for the input lads  :beer:


Looks like I will have to do some reading  up on capacitors , a classic case of Wilson running before he has even learned to crawl  :palm:


Canny stud welder Andrew  :thumbup: , good to read you got it all fixed . Used one myself many years ago  :dremel:  , I do remember one lads steel toecaps looking like two hedgehogs one morning
when he came into work   :lol:


Rob
Title: Re: Digital oscilloscope project/kit
Post by: PK on May 04, 2016, 06:27:50 PM
A simple constant current circuit is better than a resistor because it will allow faster charging.
I used this for a small anodising supply once.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on May 05, 2016, 12:30:47 PM
That sounds a much better idea PK  :thumbup: , something I will look into .


Cheers Rob
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on May 06, 2016, 05:30:07 AM
Hi
update on my non working airband receiver.
it's still not working. :doh: :doh:

I've checked all the elec caps, the're round the right way, all the chips are right way round in the correct places, I unsoldered one leg of each diode ( 4 in total ) and tested those, the're the right way.
the transistors are the right way according to the silkscreen.

I even pulled all the chips to check if I folded a leg over inserting them, all OK.

I'll try some voltage checks next.

Roy.
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on May 06, 2016, 07:06:58 AM
Roy, when you say its not working, can you elaborate a little please? Is there any audio?

Maybe theres no air traffic transmitting? :lol:
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on May 06, 2016, 08:47:58 AM
sorry, I was a bit vague  :hammer:

connecting the bnc socket to a long wire I have in the loft and touching the top of one of the chips with my finger I can barely hear a commercial radio station.

the 3 controls do nothing.

this is with a 9V battery, if I plug in a 12V wall wart the transistor mentioned previously gets hot even tho it's supposed to work on 12V.

there are a few voltages noted on the circuit diagram that came with it , one of them being 12V but there aren't as many as I would like.

I haven't had time to check them yet.

Roy.

Title: Re: Digital oscilloscope project/kit
Post by: John Swift on May 06, 2016, 10:19:02 AM
Hi Roy

the original project is here -

http://www.sentex.ca/~mec1995/circ/aviarx/aviarx.html


with 1K load resistors I don't expect the transistors to run hot
 but the TO-92 cased 78L08 regulator added to the Chinese circuit  could
 (depending the current taken by the receiver and the volt drop across the regulator)

   John


PS original circuit from http://www.sentex.ca/~mec1995/circ/aviarx/aviarx.html
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on May 06, 2016, 11:00:40 AM
 :clap: :clap: :clap: Thank you for taking the time to track down that build page John  :thumbup:

I am sure it will be a great help to me and Roy .

And the http://www.sentex.ca/~mec1995/circ/circuits.htm page looks full of interesting projects   :zap: 

Rob
Title: Re: Digital oscilloscope project/kit
Post by: John Rudd on May 06, 2016, 11:39:58 AM
The voltage regulator serves no real purpose, there's insufficient headroom from a PP3 battery to allow the reg to function....
I'd be inclined to leave it out....

Just use a current limited power supply when testing the receiver for the first time.... :zap:
Title: Re: Digital oscilloscope project/kit
Post by: nrml on May 15, 2016, 06:10:36 AM
I've just finished putting together my DSO138.
(http://i1376.photobucket.com/albums/ah18/nrml76/Mobile%20Uploads/IMG_20160515_093148590_zpsjmq7dagc.jpg) (http://s1376.photobucket.com/user/nrml76/media/Mobile%20Uploads/IMG_20160515_093148590_zpsjmq7dagc.jpg.html)

The SMT components were very easy to solder despite having absolutely zero previous experience with these. I used 0.25mm Pb/Sn solder, a pair of curved pointy tweezers and the largest chisel tip for the soldering iron that would fit on the little pads. No problems at all. In fact they were the easiest and tidiest part of the build. Some of the through hole components were a bit fiddly (the sliding switches especially) and the end product wasn't as tidy as the SMT bits but it all worked first time, so I can't really complain.

The acrylic case looks nice but there were a couple of problems. Firstly, the tabs for the sliding switches snapped the first time I toggled them and I had to remove them all. Secondly, one of the sides had slightly oversized tabs which snapped the plastic around the holes where it fits into.

Overall, it was a nice little project. Well worth the money. Now I  need to learn how to use an oscilloscope.
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on May 15, 2016, 02:36:36 PM
 :clap: :clap: :clap: :clap: looking very tidy nrml , Nice job  :thumbup:



Rob
Title: Re: Digital oscilloscope project/kit
Post by: RobWilson on May 15, 2016, 02:40:14 PM
Roy any joy with your Air band reviver ? 

Rob
Title: Re: Digital oscilloscope project/kit
Post by: wheeltapper on May 15, 2016, 04:46:24 PM
no, not yet.
I've checked everything I can think of, the circuit diagram that comes with it is no help, there are no voltages to check.

I know it's a spelling error when you called it a reviver but that's what it needs, reviving  :lol: :lol: :lol:

I've chucked it in the "to look at " box for now, it may end up in the "dump it " box.  :bang:

cheers

a disillusioned Roy.

Title: Re: Digital oscilloscope project/kit
Post by: modeng200023 on November 10, 2016, 03:40:23 AM
I started a new posting about obtaining spares from jytech in Electronics and IC Programming.

John