$20 LCR ESR Transistor checker project

[linuxguru]

yes, the more costly ones do come with m328 and backlight as mentioned in the listings for those. unfortunately low cost units like mine ($10 bo, $15 bin) cut corners in both categories. ... i should also mention that the yellow/green backlight appears much brighter than the blue ones. at least to my eyes.

The units with the M328, yellow/green backlight, and ZIF socket can be found at $20..$25, Buy-It-Now. They also have more capable firmware, including DF/Vloss measurement of capacitors, Depletion-Mode JFET measurements, etc.

The stock units with yellow backlight run the backlight and the red LED at very high currents - I changed two resistors on the board to cut the current by a factor of 10 or 20, and it's still bright enough for normal daytime use. Battery life improves enormously after this mod.

Edit: IIRC, I changed R9 and R14 to 10k to reduce the current drawn by the backlight and the red LED. Pic of modified unit shown (with the LCD panel detached to show the board). The two capacitors have been left untouched - mine came with Rubycon YXA at both locations.

[all_repair]

Just bought this:

[Macbeth]

Just bought this:

Could you have made a more smaller useless picture?

What is it? I would love to see, but... pixels...

[all_repair]

Just bought this:

Could you have made a more smaller useless picture?

What is it? I would love to see, but... pixels...

Let me dig a bigger one from the store.  My toy has not arrived.  The pitches of  3 bottom connector are just nice for the bigger MOSFET.

[neslekkim]

Looks like its this one http://www.ebay.com/itm/271367349891

[all_repair]

Looks like its this one http://www.ebay.com/itm/271367349891

Yes, same item.  I found some more interesting stuff from this store.

[casinada]

I was looking at that same one yesterday: Rechargeable Battery, test Zeners with up to 50V but why use the 168 and not the 328?
I don't think the shorting cap relay is implemented. It would be nice to see the PCB. What is the meaning of that 9V battery next to the unit?
Please post pictures once you get it.
Nice case

[madires]

The units with the M328, yellow/green backlight, and ZIF socket can be found at $20..$25, Buy-It-Now. They also have more capable firmware, including DF/Vloss measurement of capacitors, Depletion-Mode JFET measurements, etc.

Don't worry about the firmware! Get the latest and greatest at http://www.mikrocontroller.net/svnbrowser/transistortester/Software ;-)
I commend to buy only clones with ATmega328 since new features and most improvements require >16kB flash. If you got an older/cheaper one with an ATmega168 it makes sense to replace it with an ATmega328.

[obd.tech]

i'm new to this gadget and forum https://www.eevblog.com/forum/Smileys/default/smiley.gif, is the newest firmware 1.09? i looked at the link above and got a little confused :-)
whats the 'Programm fuer Optionen WITH_SELFTEST und AUTO_CAL ueberarbeitet' all about?
Thanks
p.s. how do you put a smiley in the post text?

[madires]

i'm new to this gadget and forum is the newest firmware 1.09? i looked at the link above and got a little confused :-)
whats the 'Programm fuer Optionen WITH_SELFTEST und AUTO_CAL ueberarbeitet' all about?

The latest version (1.10k) is always in "trunk" and my alternative firmware (1.10m) in "markus". To download the directory click "Download GNU tarball".

p.s. how do you put a smiley in the post text?

This way: Just above the editor window you should see all emoticons. Click the one you like to add and it will be added at the cursor's position.

[obd.tech]

 Thanks for your help , i look forward to playing with my new toy and the things i hope to test & fix with the help and knowledge from this forum . Keep up the good work guy's https://www.eevblog.com/forum/Smileys/default/icon_smile_thumbsup.gif

mmm......smileys don't work for me.....i clicked but nothing.....i can only drag one down.....then it comes out wrong :-(
What am i doing wrong?

[sleemanj]

It has to be a custom modification to support that LCD and include the extra symbols. Unfortunately the vendor doesn't seem to care about the project's Open Source Hardware nature.

FWIW, this appears to be the people who "developed" the large repurposed LCD version, fish8840 on Taobao.
http://item.taobao.com/item.htm?spm=a230r.1.14.35.QG5YBf&id=36323329572

[all_repair]

I was looking at that same one yesterday: Rechargeable Battery, test Zeners with up to 50V but why use the 168 and not the 328?
I don't think the shorting cap relay is implemented. It would be nice to see the PCB. What is the meaning of that 9V battery next to the unit?
Please post pictures once you get it.
Nice case

Fresh, not yet power up.  It is 328 uC.  But on the Taobao Chinese site, they said that it could range from 168 to 328.  As I mentioned on another post, those selling on ebay are normally trader and they could be carrying the old version.

[Jerby]

I build this tester and it works great. But it would be nice to have it on a PCB. Does anyone know if there are PCB's available, or batches to come?

[Skimask]

It's ~$20 on eBay.
Is your time worth that little?

[moemoe]

I build this tester and it works great. But it would be nice to have it on a PCB. Does anyone know if there are PCB's available, or batches to come?

I created one (SMD), can be ordered eg via oshpark. https://github.com/maugsburger/avr-component-tester

[rr100]

Got the one from post #277, seems to do what it says on the tin, backlight display&all, micro on DIP socket. "not on" current really low like 0.02 microamps (but that's my last digit on my multimeter so don't trust it much except as ... really low). I don't think backlight will be much of a problem to the battery as it shuts down itself rather quickly (but still not annoyingly quick).

[guido]

have the same one and made the following changes:

  - two SMD 47nF caps added to AVCC, DVCC to gnd (on the pins). Original cap removed
  - MC1403 2.5V reference added to pin27 (happened to have that one in the parts bin)
  - ic socket replaced with a good one
  - latest sw version

to do
 - change measurement resistors to 0.1% types (680/470k).

[rr100]

Did not manage to break the ZIF socket yet (I don't think is particularly bad, probably it might break if you put something thicker and you try to close it but works.

On what I can double check it seems to get 2 significant digits (note: that's not the same as 1%!), all in all quite satisfied.
I think it wouldn't be hard to include some marginal input protection and the requiered analog stage to make it measure something like 0-100V at least and maybe one shunt just to have everything completed as a small multimeter (it can be made much compact if needed, mine is all through hole).

I would really use such a toy, sometimes you just need a multimeter but is not critical enough and is not ofthen enough and I can't justify the weight of a full unit (even a small one). I got to a point where I was checking batteries with a bus pirate (which I had with me because I needed now and then for the serial capabilities). This has everything it needs, including a display!

[madires]

On what I can double check it seems to get 2 significant digits (note: that's not the same as 1%!), all in all quite satisfied.
I think it wouldn't be hard to include some marginal input protection and the requiered analog stage to make it measure something like 0-100V at least and maybe one shunt just to have everything completed as a small multimeter (it can be made much compact if needed, mine is all through hole).

That's something we should consider for a future Tester+. The nice thing about the current design is that it is very simple and easy to build. The other important point is the firmware compatibility. The k-version supports several modifications meanwhile and it's quite hard to check all variations for each code change. Supporting several different hardware versions makes the firmware development much more complicated.

[madires]

The new m-version 1.11m is released (http://www.mikrocontroller.net/svnbrowser/transistortester/Software/Markus/). What's new?
- several minor improvements
- BJTs with base emitter resistor
- BJTs with freewheeling diode on the same substrate
- detection of (un)symmetrical drain and source for depletion mode FETs
- detection of body diode for depletion mode FETs
- improved pinout detection for Triacs (G, MT1 & MT2)

[SeanB]

Got mine this week, and it is good enough to use for checking semiconductors, mid range capacitors and resistors. Going to keep it in my tool box for general quick testing.

[rr100]

Just bought one of these, (hope i picked correctly)
http://www.ebay.com.au/itm/200960094152?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

It's one of the standard clones with an ATmega328. Might need an ISP header for firmware updates.

Will probably upgrade the firmware every now and then, any advantage in adding the ISP header versus taking the micro out (is on a socket)?

[madires]

Will probably upgrade the firmware every now and then, any advantage in adding the ISP header versus taking the micro out (is on a socket)?

Less mechanical stress. Choose whatever suits you better.

[eevbstedt]

Does anyone know where an English version of the 'changelog.txt' file located here?
http://www.mikrocontroller.net/svnbrowser/transistortester/Software/tags/

Just picked up a newer version of the tester off ebay and am looking for firmware options.  I've attached a copy of the file for easier access.


Update:
I put the file through Google Translate and came up with this (I've cleaned it up a little).  Can you take a peek and give feedback?  Thanks!