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CNC / Re: DDCSV1.1 4 Axis controller
« Last post by WeldingRod on Today at 12:56:59 PM »
Will,  I tested and using S24000 gives me a speed of 24000 RPM on the display.

I messed with the time-based settings but I can't get the speed to ramp up rapidly; it takes at least 3 seconds to go from zero to full speed.  Frustrating for laser work...

BTW, first CNC laser with my Ox!  Next up is to actually use the rotary axis; that's why the laser has the weird offset mount.
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Electronics & IC Programing / Re: How do you terminate your coax to BNC?
« Last post by PekkaNF on Today at 11:32:09 AM »
Kiitti Esko,

I'll try that one. I have hacked few connectors 50% right: they had pint that could be soldered.

This far I have managed with mutilated readily crimpped cable etc. but I see that I am spending more time with different pieces of cabling, connectors and stuff.

At work there were trained porfessionals that would do hard part. Now I am on my own with my hobbies and I realize that there were questions I should have made (and surplus material I should have begged).

Next quesion: At the end of the thin 50 ohm coax I need short pigtails, which (readily) available wire would be good? Flexible ethernet twisted pair?
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Gallery / Re: homemade tool & cutter grinder (step by step)
« Last post by celsoari on Today at 10:05:20 AM »
part 5:
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Pekka,
I have (at home, now in Frankfurt) about 200 different BNC connectors, variety of coax cables - and no crimping equipment.

I think I have tried it all.

The best so far has been to:
1. peel off about 20 mm of the outermost palstic shield
2. solder the center pin so that the coax insulator "meets" the pin
3. Push the pin and the coax (now soldered) into the connector
4. Pull the coax copper shilding over the connector
5. Wrap copper wire around the part of the coax shield which is overlapping the connector shield
6. cut off excess coax shield
7. Solder the shield into the connector

Although the coax insulation may melt somewhat I have never succeeded to create a short there

The result will NOT win any beauty contest but it works. You may camouflage the connection by shrink tubing.
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Electronics & IC Programing / Re: How do you terminate your coax to BNC?
« Last post by Will_D on Today at 08:30:58 AM »
Surely Farnell or Radionics would stock crimpers ( at a price  :bugeye: )

Cheers

Will
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Electronics & IC Programing / How do you terminate your coax to BNC?
« Last post by PekkaNF on Today at 08:18:28 AM »
We were pampered 30 years ago in school electronics lab. No shortage of test leads.

There is usually vety little point of rolling your own BNC/RG58 stuff, but on RG174 or RG316U cables, and panel connectors etc.

I'm having a hard time finding crimpping pliers for AF 1,75 mm pin and 5,6 mm sleeve.

https://www.tme.eu/fi/details/5-1634500-1/bnc-liittimet/te-connectivity/

Dimenssions:
https://www.tme.eu/fi/Document/11a4780343b55fee08f6e9023cade175/5-1634500-1.pdf
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Electronics & IC Programing / Re: Simple TTL signal generator/counter with sum
« Last post by PekkaNF on February 22, 2018, 05:45:50 PM »
My signal generator sucks.

Need better buffer for TTL. Would something like this do? Sans oscilator



Testing small test probe, idea from here:
http://jahonen.kapsi.fi/Electronics/DIY%201k%20probe/

Put some pogos on dupont connectors. These will hook on normal pin strip and on most connectors.

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Electronics & IC Programing / Re: Simple TTL signal generator/counter with sum
« Last post by eskoilola on February 22, 2018, 11:34:45 AM »
Well. One can, of course, harness an entire buffer to output the needed power. Another option would be to use small low threshold N and P fets connected fae-to-face. Of course one needs some sort of current limitation as these WILL conduct at same time, being a very short time that could be two tiny inductors.

I made a largeish FET gate driver circuit that was capable of outputting 15 V/pp into a 0.47uF capacitor @ 10KHz. The test capacitor fried - of course - just in 2 seconds. The output current was in the 20A region. This kind of circuitry is needed when FET array (many fet's in parallel) need to be switched on/off very rapidly. In this case the array consisted of 27 high current, medium voltage FET's. The gate capacitance was 0.1uF all together including the miller capacitance. The driver used the face-to-face FET topology which I have found to be quite easy to get going.
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Electronics & IC Programing / Re: Simple TTL signal generator/counter with sum
« Last post by AdeV on February 22, 2018, 08:08:53 AM »
Sounds like an ideal application for a smallish FPGA; but I don't know if you can get those in "hobbyist friendly" formats (i.e. DIP).
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Our Shop / Re: Another machine joins the stable...
« Last post by AdeV on February 22, 2018, 08:05:29 AM »
New job in the UK... unfortunately it means a long-ish commute every day, but for close to double the money, it's worth it. 12-18 months there, then I'll look for something more convenient...
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