$20 LCR ESR Transistor checker project

[opty]

Hi everyone!
Someone might have asked that already in this threat but what is in your opinion the best one out of those many versions?
Thanks for your replies!
Greetings,
Jannis

!!!MOST important read ttester.pdf and other info!!! from
http://www.mikrocontroller.net/svnbrowser/transistortester/Doku/trunk/pdftex/english/

-> ttester.pdf 2.5 Chinese clones
and some hints on modding (better voltage ref; docoupling cap; etc.)

Then in my opinion (without particular order)
* ATMega328 (some have 168); I prefer socketed atmega just in case I need to replace (never actually happened )
* SPI area for in socket updating (although not that necessary if proc is in socket)
* 16x2 lcd - you don't need those fancy clones; just use standard software (and upgrades) from http://www.mikrocontroller.net
* watch our for cheap mods

[mauroh]

SOLVED_1!!! "Different values with different firmwares"
Thank you madires, answering to my latest question you gave me the hint to clear the mistery of the incorrect measurement with different firmware versions:
I'm using the TL866A to upload the firmware and I wasn't  noticing that by default it loads correctly the .hex files as INTEL HEX, but the .eep files as BINARY!!!
Basically I was loading garbage on the data memory and only by accident the older versions where measuring correctly 

SOLVED_2!! "m-firmware .eep file too big"
Same as before, loading the .eep file as INTEL HEX it actually fit on the eeprom and the m-firmware is now up and running 
I noticed that the text alignament on the screen is not perfect and there are some dots on the left of the screen (see attachment).
I'll verify the config.h and make file...

SOLVED_3!! "TRIACs not identified"
Just to prove the point I tested some other TRIACS and found one that is correctly identified (no PN  )

ON Going "UART"
Is it too late to do it now...

I attached a picture of the case I modified to accomodate the ZIF.
I hate the white connector that came with the enclosure and I much prefer the ZIF!!
Yes I made my custom faceplate 

Thanks
Mauro

[all_repair]

First I want to thanks the hero here that are improving the tester almost non-stop.  I better don't mention names as likely I shall left out some.
I bought 3 LCR ESR testers so far.  There is a LCR-T6 just released that has the IR receivers.   I have not updated and upgraded my sets as I was and still waiting for the best time to do the upgrade    .  But the LCR-T6 still does not have the encoder and likely without the relay so I am going to skip. 
Has anyone modified a LCR-T5 or LCR-T4 or any other china $20 tester to include the encoder and the relay protection?

[madires]

SOLVED_2!! "m-firmware .eep file too big"
Same as before, loading the .eep file as INTEL HEX it actually fit on the eeprom and the m-firmware is now up and running 
I noticed that the text alignament on the screen is not perfect and there are some dots on the left of the screen (see attachment).
I'll verify the config.h and make file...

Glad you found the cause. Please try to enable or disable "#define LCD_OFFSET_X" in the M12864 section in config.h. The ST7565 uses 132 columns internally while the display has just 128 columns. The option above shifts the display output by 4 pixels which is often needed when the output is vertically flipped.

[demetris]

@all_share can you share some info on the protection relay you are talking about?
Will it help with charged capacitors not blowing out the tester/soc?

[garnix]

I attached a picture of the case I modified to accomodate the ZIF.
I hate the white connector that came with the enclosure and I much prefer the ZIF!!
Yes I made my custom faceplate 

May I ask how you fixated the ZIF on the case? Just glued it on? And then you just soldered some wires to the PCB?

I ordered the same board and case, so I might do a similar modification ;-)

[Seekonk]

I just bought one of these $12 wonders to use at my camp which is 12V.  Tested a capacitor and the value was close, but the ESR read 18 ohms.  Choose a lot of different value caps (other than electrolytics) and it is still 18 ohms.  Place a 51 ohm resistor in series with the cap and it is still reads 18 ohms. Actually, this is about what I expected.  I think it is a very handy device.  Just don't take the numbers too seriously.

[Macbeth]

I just bought one of these $12 wonders to use at my camp which is 12V.  Tested a capacitor and the value was close, but the ESR read 18 ohms.  Choose a lot of different value caps (other than electrolytics) and it is still 18 ohms.  Place a 51 ohm resistor in series with the cap and it is still reads 18 ohms. Actually, this is about what I expected.  I think it is a very handy device.  Just don't take the numbers too seriously.

Or consider you have a faulty unit! 

[mauroh]

@madires:
Yep, commenting the line #define LCD_OFFSET_X , the LCD allignament is fine, thank you!!

@demetris:
At page 11 of the excellent firmware documentation (http://www.avrtester.tode.cz/upload/ttester_en.pdf) is it clearly described how to add protections with relay or diodes.

@garnix:
NO GLUE/WIRES THANK YOU!!!!  See attached few pictures of the super easy mod.
I have to say that even though I like to have the possibility to easily replace the ZIF also with something different like an SMD adapter, I think I will lower it and cut the edge of the case like the LCR-T6 (see picture)

See attached the list of all the changes I made so far on the config.h to have my M12864 DIY KIT (Banggood) working almost perfectly with the m-firmware.
I wrote almost perfectly, because the "Adjustment" option fail and I dont know why. I'll do some other tests....
Now I'm going back to the k-firmware to play with the UART

Mauro

[Seekonk]

I just bought one of these $12 wonders to use at my camp which is 12V.  Tested a capacitor and the value was close, but the ESR read 18 ohms.  Choose a lot of different value caps (other than electrolytics) and it is still 18 ohms.  Place a 51 ohm resistor in series with the cap and it is still reads 18 ohms. Actually, this is about what I expected.  I think it is a very handy device.  Just don't take the numbers too seriously.

Or consider you have a faulty unit! 

I contend that any ESR reading of a capacitor below 1uF with these devices is bogus.
Again, I measured a .33uf capacitor with a 51 ohm resistor.  It read 2.2 ohms without
the resistor and 14 ohms with the resistor.  On another machine it read 1 ohm and 53
ohms respectivly as it should.  I invite everyone to make similar tests with a variety
of capacitor values.  I suggest these programs surpress ESR readings on the display
beyond certain values since they have no relation to reality.

[retrolefty]

I just bought one of these $12 wonders to use at my camp which is 12V.  Tested a capacitor and the value was close, but the ESR read 18 ohms.  Choose a lot of different value caps (other than electrolytics) and it is still 18 ohms.  Place a 51 ohm resistor in series with the cap and it is still reads 18 ohms. Actually, this is about what I expected.  I think it is a very handy device.  Just don't take the numbers too seriously.

Or consider you have a faulty unit! 

I contend that any ESR reading of a capacitor below 1uF with these devices is bogus.
Again, I measured a .33uf capacitor with a 51 ohm resistor.  It read 2.2 ohms without
the resistor and 14 ohms with the resistor.  On another machine it read 1 ohm and 53
ohms respectivly as it should.  I invite everyone to make similar tests with a variety
of capacitor values.  I suggest these programs surpress ESR readings on the display
beyond certain values since they have no relation to reality.

 As long as this thread had been going for I'm surprised not recalling anyone ever validating the basic accuracy of the capacitance, resistance, ESR and Beta measurement results compared to other test equipment. Anyone recall testing and quantifying the accuracy?

[CustomEngineerer]

I contend that any ESR reading of a capacitor below 1uF with these devices is bogus.
Again, I measured a .33uf capacitor with a 51 ohm resistor.  It read 2.2 ohms without
the resistor and 14 ohms with the resistor.  On another machine it read 1 ohm and 53
ohms respectivly as it should.  I invite everyone to make similar tests with a variety
of capacitor values.  I suggest these programs surpress ESR readings on the display
beyond certain values since they have no relation to reality.

A quick testing with 2 of the cheap testers (both M12864 - http://www.banggood.com/DIY-M12864-Graphics-Version-Transistor-Tester-Kit-LCR-ESR-PWM-p-986954.html) and an Agilent U1733C (@10kHz). The first column of values is from a M12864 with K firmware v1.12k r555. The second column of values is M12864 with M firmware v1.20m-trendy. Third column of values is the Agilent U1733C at 10kHz test frequency. Values are close enough for me.

                             M12864-K     M12864-M     U1733C
1uF Eloctro            3.6ohm        3.61ohm        3.813ohm
0.47uF Electro       4.1ohm        3.91ohm        4.218ohm
0.47uF Electro       3.8ohm        4.09ohm        4.068ohm
0.33uF Tantalum   3.5ohm        2.68ohm        3.522ohm
0.10uF Tantalum   9.7ohm        NoEsr            10.236ohm

[CustomEngineerer]

From the K firmware manual (ttester.pdf, pg42).

"You should not expect very good accuracy of measurement results, especially the ESR measurement and the results of inductance measurement are not very exact."

There is also a lot of other good information in the manual for how the testers actually test the ESR (as well as all other measurements) and what to expect.

[CustomEngineerer]

I suggest these programs surpress ESR readings on the display beyond certain values since they have no relation to reality.

I'm pretty sure madires or someone else confirmed this many pages back in this thread. Quick search didn't find it, but really remember this being discussed.

Edit: Also supposed to suppress the ESR reading if the measured value is lower than internal resistance of the pins.

[timofonic]

I suggest these programs surpress ESR readings on the display beyond certain values since they have no relation to reality.

I'm pretty sure madires or someone else confirmed this many pages back in this thread. Quick search didn't find it, but really remember this being discussed.

Edit: Also supposed to suppress the ESR reading if the measured value is lower than internal resistance of the pins.

Just for the laymen still unable to process that amazing project:

Why is  limited?
How would get improved? Would make it substantially more expensive?

[mauroh]

A quick testing with 2 of the cheap testers (both M12864 - http://www.banggood.com/DIY-M12864-Graphics-Version-Transistor-Tester-Kit-LCR-ESR-PWM-p-986954.html) and an Agilent U1733C (@10kHz). The first column of values is from a M12864 with K firmware v1.12k r555. The second column of values is M12864 with M firmware v1.20m-trendy. Third column of values is the Agilent U1733C at 10kHz test frequency. Values are close enough for me.

                             M12864-K     M12864-M     U1733C
1uF Eloctro            3.6ohm        3.61ohm        3.813ohm
0.47uF Electro       4.1ohm        3.91ohm        4.218ohm
0.47uF Electro       3.8ohm        4.09ohm        4.068ohm
0.33uF Tantalum   3.5ohm        2.68ohm        3.522ohm
0.10uF Tantalum   9.7ohm        NoEsr            10.236ohm

Wow thank you so much.
The result is quite impressive for a 17Euro circuit and surely good enough for my needs.
Again, kudos to the developers 
Anyway as always with all the test measurement tools, a bit of judgement on the measured values is needed depending on the specific component/situation/implementation of the measure...   

In this days I made some tests enabling the UART on the K-firmware and it works really well.
I was thinking to write a small Processing sketch to display the measurement on a big PC panel

I also need to test this supercap https://www.maxwell.com/images/documents/bcseries_ds_1017105-4.pdf  (see page 3) and I will read the K-firmware documentation to verify if this can be achieved. Was this already discussed??

Mauro

[madires]

I also need to test this supercap https://www.maxwell.com/images/documents/bcseries_ds_1017105-4.pdf  (see page 3) and I will read the K-firmware documentation to verify if this can be achieved. Was this already discussed??

The theoretical limit for capacitance is 100mF but I'd say the working limit is about 20mF. Goldcaps can't be measured at all (mostly detected as a diode or two anti-parallel diodes).

[madires]

I suggest these programs surpress ESR readings on the display beyond certain values since they have no relation to reality.

I'm pretty sure madires or someone else confirmed this many pages back in this thread. Quick search didn't find it, but really remember this being discussed.

Edit: Also supposed to suppress the ESR reading if the measured value is lower than internal resistance of the pins.

The m-firmware measures the ESR only for caps >180nF and any problem with the measurement will suppress the display of the ESR value. IIRC there is also a lower capacitance limit for the k-firmware. And it uses two different timings which improves the ESR measurement for small capacitances.

[Seekonk]

Just for reference for anyone else, this version isn't very good.  http://www.ebay.com/itm/271972464770?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[mauroh]

I also need to test this supercap https://www.maxwell.com/images/documents/bcseries_ds_1017105-4.pdf  (see page 3) and I will read the K-firmware documentation to verify if this can be achieved. Was this already discussed??

The theoretical limit for capacitance is 100mF but I'd say the working limit is about 20mF. Goldcaps can't be measured at all (mostly detected as a diode or two anti-parallel diodes).

Not studied yet the issue, but since this could be handy for a project, I was thinking to make a specific firmware function.
At page 3 of the datasheet i linked, there is the method to measure C and ESR of this beasts.
Is this a similar method implemented in the m and k firmware? (I'll read the documentation....)

The only limitation I can see is the time it will take the test, but this is not an issue for my needs.
Is there something else that will require a hardware change?

Thanks
     Mauro

[Gyro]

Just for reference for anyone else, this version isn't very good.  http://www.ebay.com/itm/271972464770?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Actually it's not bad with updated f/w. It's known in this thread as the LCR-T4, check from post #939 approx. It's very cheap and easy to mount (Display quite close to the PCB). It does benefit from some more supply decoupling caps and maybe a change of reference IC (although the TL431 on board is ok). It's not a good choice if you want to start adding encoders for additional functions however.

[upsss]

@Gyro, I have this exact tester which I payed $11 for it on AliExpress.  I am curious why do you say "It's not a good choice if you want to start adding encoders"?  I have one of this rotary encoders on order and I am planning to install it.  Once I get all the parts I am also planning to replace the 9V battery with a rechargeable Li-Ion and add a protection relay.

[madires]

The only limitation I can see is the time it will take the test, but this is not an issue for my needs.
Is there something else that will require a hardware change?

Just the 30 odd Ampere test current The tester can deliver 7mA (safely).

[Gyro]

@Gyro, I have this exact tester which I payed $11 for it on AliExpress.  I am curious why do you say "It's not a good choice if you want to start adding encoders"?  I have one of this rotary encoders on order and I am planning to install it.  Once I get all the parts I am also planning to replace the 9V battery with a rechargeable Li-Ion and add a protection relay.

Nothing specific, only that it is smd rather than through-hole like some of the others and very compact. There seem to be other ebay boards available now that include encoders, frequency inputs / outputs, voltage measurement etc. Some boards have Li-Ion psu built in too.

As my post hopefully conveyed, I like this board, I use it myself (together with a protection relay), but I have no need to extend it to additional functions or alternate power sources so haven't explored ease of expansion further than the relay. It's a good basic, accurate board and also cheap to replace if needed. I have no idea what Seekonk's issue with it was.

[nowlan]

Not sure if this one is related, but looks to be junk.