DIY Test Gear

[simba15]

So I seem to always be looking for DIY test equipment

It might be great to have a thread of projects that members have build or experiences or jsut think are great.

There are tons of them that I can find, but hard to say if they are good or the best. (I prefer simple ones with single side pcb and DIP chips)

A few ideas would be

PC Oscilloscope:
http://electronics-diy.com/electronic_schematic.php?id=703
https://www.martinloren.com/hs40x-diy-oscilloscopes/
https://www.electronicsforu.com/electronics-projects/pc-based-oscilloscope-using-arduino
https://github.com/fhdm-dev/scoppy  (my fav)

Function generator:
http://electronics-diy.com/1hz-to-1mhz-xr2206-function-generator.php
http://www.vwlowen.co.uk/arduino/xr2206/XR2206-function-generator.htm
https://circuitdigest.com/microcontroller-projects/arduino-waveform-generator

Power Supply:
http://www.electronicecircuits.com/electronic-circuits/variable-power-supply-0-24v
https://solderingmind.com/diy-variable-power-supply-with-adjustable-voltage-and-urrent/

Programmable Load:
https://juangg-projects.blogspot.com/2019/02/arduino-based-electronic-load.html
https://circuitdigest.com/microcontroller-projects/adustable-electronic-dc-load-using-arduino


I hope others feel they can contribute and put forth any other projects and results.

I would love to document a series of DIY test tools that any beginner can build for a reasonable price.

[Bud]

We had such thread , i do not have a link though. There was cool stuff people posted in it.

[Andrew_Debbie]

I've got a few personal projects.  All are simple.  None of them are fully documented.   If there is enough interest I can put them on Github.
They are all based on a 100x100 or 100x50mm PCB.     The PCBs mount on a 100x100 or 100x50 base plate, which saves on a case.   The base plates are KiCad templates.

5V and 3.3V buck-boost --> linear supply which can be battery powered, or from an off-board supply.   I built this as an easy way to get isolated power for another 50x100 module.   Swap two parts for a different pair of voltages. 



Inexpensive modulated 455kHz signal generator.   Useful for repairing old radios, since most of  them use 455kHz IF.   *This is mostly copied from an old magazine construction article which shows how to build it on strip board. I first built this many years ago and decided to make it again as a 50x100mm module.




Unregulated  linear DC power supply.  Uses Amveco/Talema 25VA transformer. Has input filter.   Of course this needs to go in a case not on a plate.



I've got several more modules in various stages of development.   

 

[bob91343]

I like the TDR pulser, and the low resistance Ohmmeter.  And the noise bridge.

[devinatkin]

I need to make a nano-voltmeter for research purposes, it's not the center point of the research but is going to be essential to getting good results. (Can't use off the shelf stuff cause it needs to be cheap and ruggedized to be hauled out to the middle of nowhere and run off a battery pack, target BOM $100-300). If I'm actually successful in getting good results I certainly plan to document and release it. If someone is aware of an existing project which I can either clone or purchase in that price range I'd be eternally grateful.

I keep making excuses to kick the design down the road, but I've got to get a proper start on it by the week after next at the latest.

[simba15]

We had such thread , i do not have a link though. There was cool stuff people posted in it.

Interesting i wonder how to find it ( keywords are kinda vauge here)

Thanks everyone for there contributions!

Here are a few more (more complex, not single side pcb and dip chips here)

EEZ Power supply:
https://github.com/eez-open/psu-hw

32 bit Sigma-Delta ACD (8.5 digit muitimeter (Marco reps)
https://ohwr.org/project/opt-adc-10k-32b-1cha/wikis/home

[Andrew_Debbie]

There are many projects on Hackaday.

Here are a few I've bookmarked.    I have not built any of them.

https://hackaday.io/project/164913-open-power

https://hackaday.io/project/4407-elbsupply-simple-linear-bench-supply

https://hackaday.io/project/179429-ntp-based-digital-clock-panel-driver   This one isn't TE, but has elements than could be reused as part of something else.


https://hackaday.io/project/12934-chirp-a-low-cost-function-generator

https://hackaday.io/project/24832-psu-burner

[not1xor1]

Power Supply:
http://www.electronicecircuits.com/electronic-circuits/variable-power-supply-0-24v

just had a quick look at that.
it is ugly (it might have been good 70 years ago when the first BJTs became available) and the schematic does make no sense as the collectors of T1 and T2 should be connected to the anode of D2 whose only purpose is to reduce the effect of the ripple voltage for the zener reference. Current limit is rather coarse and inefficient. There are tons of better schematics.

[Bud]

We had such thread , i do not have a link though. There was cool stuff people posted in it.

Interesting i wonder how to find it ( keywords are kinda vauge here)

Found it

https://www.eevblog.com/forum/testgear/show-the-homemade-equipment-you-are-using-now/

[simba15]

Power Supply:
http://www.electronicecircuits.com/electronic-circuits/variable-power-supply-0-24v

just had a quick look at that.
it is ugly (it might have been good 70 years ago when the first BJTs became available) and the schematic does make no sense as the collectors of T1 and T2 should be connected to the anode of D2 whose only purpose is to reduce the effect of the ripple voltage for the zener reference. Current limit is rather coarse and inefficient. There are tons of better schematics.

Thanks for checking it! I will remove it as its best not to highlight the poor designed ideas.

Can you provide any better designs?

Thanks.

[simba15]

We had such thread , i do not have a link though. There was cool stuff people posted in it.

Interesting i wonder how to find it ( keywords are kinda vauge here)

Found it

https://www.eevblog.com/forum/testgear/show-the-homemade-equipment-you-are-using-now/

Thanks! Some good ones in there!

Do you have any more info about the USB/GBIP adapter you made?

Could use a few.

[kripton2035]

low ohm meter and short circuit finder
http://kripton2035.free.fr/Projects/shorty-display.html

[Andrew_Debbie]

Modulated 455kHz signal generator complete. 

This is a low cost signal generator for troubleshooting.   

I'm happy to share details if anyone wants to copy it.   Eventually I will put the files on github.    Original idea came from an old magazine article.

[bob91343]

You could bring down the frequency a bit by increasing C4 and/or C5.

[free_electron]

Elektor had a whole pile of test euipment they published in the 80's and 0. i built many of them. function generator , pulse generator , capacitor meter , power supply ,  quadrant supply, multimeter , lrc meter , frequency counter.
use internet archive to find the information

[pcprogrammer]

I'm playing around with a lichee nano, an Anlogic FPGA module, an AN9767 DAC module and an AD9226 ADC module. Not much working yet, but it can become a nice multiple in one instrument. Not super high frequency, but the DAC is 14 bits and can run on 125MHz. The ADC is 12 bits and can do 65MSa/s.

First up is an AWG or DDS. Making FPGA programming in verilog is new for me so a lot of trial and error, but I managed to get it running on 125MHz outputting a sawtooth on 7629Hz. Also able to get a variable frequency but something is wrong in the FPGA programming, because the second channel does not work properly.

It is for fun and learning FPGA. The lichee nano is reasonable capable for doing the human interface and displaying.

It will end up in my lichee nano repository: https://github.com/pecostm32/Lichee_Nano There already is some stuff in there about the hardware and some test software.

I don't have a 3D printer so used a bit of left over wood to stick it on.

[Andrew_Debbie]

You could bring down the frequency a bit by increasing C4 and/or C5.

I might.  It is already  close enough for troubleshooting old AM radios, which is what I use it for.

455kHz ceramic resonators are cheap but not high precision.   The part I'm using is rated +/- 2kHz at 25C.  It can drift a few tenths of a percent with temperature.