Author Topic: Digital oscilloscope project/kit  (Read 123599 times)

Offline wheeltapper

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Re: Digital oscilloscope project/kit
« Reply #275 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.
I used to be confused, now I just don't know.

Offline PekkaNF

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Re: Digital oscilloscope project/kit
« Reply #276 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

RobWilson

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Re: Digital oscilloscope project/kit
« Reply #277 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

Offline wheeltapper

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Re: Digital oscilloscope project/kit
« Reply #278 on: March 06, 2016, 01:13:22 PM »
Yay Pekka, welcome to the nuthouse club.  :D :D

Roy.
I used to be confused, now I just don't know.

Offline PekkaNF

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Re: Digital oscilloscope project/kit
« Reply #279 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

Offline wheeltapper

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Re: Digital oscilloscope project/kit
« Reply #280 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.
I used to be confused, now I just don't know.

Offline PekkaNF

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Re: Digital oscilloscope project/kit
« Reply #281 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

Offline John Stevenson

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Re: Digital oscilloscope project/kit
« Reply #282 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.
John Stevenson

Offline PekkaNF

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Re: Digital oscilloscope project/kit
« Reply #283 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
« Last Edit: March 19, 2016, 04:55:56 AM by PekkaNF »

Offline wheeltapper

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Re: Digital oscilloscope project/kit
« Reply #284 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.
I used to be confused, now I just don't know.

RobWilson

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Re: Digital oscilloscope project/kit
« Reply #285 on: April 02, 2016, 06:54:27 AM »
Hi Roy

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

 

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

Offline wheeltapper

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Re: Digital oscilloscope project/kit
« Reply #286 on: April 02, 2016, 07:44:06 AM »
Oh all right then :)



mustn't break the rules.  :mmr:

cheers.
Roy.

I used to be confused, now I just don't know.

RobWilson

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Re: Digital oscilloscope project/kit
« Reply #287 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

RobWilson

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Re: Digital oscilloscope project/kit
« Reply #288 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

Offline wheeltapper

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Re: Digital oscilloscope project/kit
« Reply #289 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.

I used to be confused, now I just don't know.

Offline wheeltapper

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Re: Digital oscilloscope project/kit
« Reply #290 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.
I used to be confused, now I just don't know.

RobWilson

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Re: Digital oscilloscope project/kit
« Reply #291 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

Offline wheeltapper

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Re: Digital oscilloscope project/kit
« Reply #292 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.
I used to be confused, now I just don't know.

RobWilson

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Re: Digital oscilloscope project/kit
« Reply #293 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:

Offline hermetic

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Re: Digital oscilloscope project/kit
« Reply #294 on: April 02, 2016, 12:47:43 PM »
The plan is "There is no plan", that's the plan! (Marx Brothers)

Offline wheeltapper

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Re: Digital oscilloscope project/kit
« Reply #295 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:
I used to be confused, now I just don't know.

RobWilson

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Re: Digital oscilloscope project/kit
« Reply #296 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 



Offline wheeltapper

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Re: Digital oscilloscope project/kit
« Reply #297 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.
I used to be confused, now I just don't know.

RobWilson

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Re: Digital oscilloscope project/kit
« Reply #298 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

Offline wheeltapper

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Re: Digital oscilloscope project/kit
« Reply #299 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.

I used to be confused, now I just don't know.