$20 LCR ESR Transistor checker project

[madires]

It uses JLX12864G-086 Display Module, with UC1701x Controller.

What firmware Configuration can I use?

At first glance it seems to be compatible with the ST7565. So please try ST7565.

[madires]

would be nice to have a compilation for Example : an 128x64  graphic lcd based on ks0108    they are cheap for 10$ on Ebay

bigger is better  loll 

I have a old mega 2560 sitting duck in my drawer ...

The k-firmware supports the ATmega 2560, but not KS0108 based LCDs.

[texaspyro]

I installed the 1.25m firmware on a 16 Mhz AY-AT board.  Seems to work well, but I haven't done much with inductors.

One thing that I noticed is that blue text on the black background is VERY difficult to read (particularly when the sign-on / bye splash screens flash by in under a second)  Perhaps a more contrasty color would a better choice.  People had a similar issue in Lady Heather and I changed the blue to a lighter, more violet palette... it's still not all that good, but I needed to display 14 more-or-less distinct colors and a shade of blue was needed.   White or yellow shows up quite well against black.

Also, any plans to implement the FET Rds-on and body diode Vf measurements that 1.12k does?

[chick0n]

It uses JLX12864G-086 Display Module, with UC1701x Controller.

What firmware Configuration can I use?

At first glance it seems to be compatible with the ST7565. So please try ST7565.

"mega328_T3_T4_st7565" works, with slight Modifications.

But I cant get it calibrated.

When I short the 3 testports, it shows "self test?" then measures ohm between testports, then it shows "not calibrated!" again. No differences when I press the Button.

[stj]

when it says "self test?" press the button.

[chick0n]

when it says "self test?" press the button.

It measures ohms, if I press the Button or not. then shows not calibrated

[stj]

no, your not fast enough.
you short the 3 pins together, then turn it on.
it says "self test?" and you press the button quickly to go into calibration mode.

the only other time i have seen it constantly say it's not calibrated is when the eeprom was not programmed properly.

[indman]

Hi, madires!
Whether it is possible to make in your firmware the same mode of the continuous measurements, how at Karl-Heinz?
That is, that the display wasn't cleared every time in case of new measurement, and only the tested value changed?

[madires]

One thing that I noticed is that blue text on the black background is VERY difficult to read (particularly when the sign-on / bye splash screens flash by in under a second)  Perhaps a more contrasty color would a better choice.  People had a similar issue in Lady Heather and I changed the blue to a lighter, more violet palette... it's still not all that good, but I needed to display 14 more-or-less distinct colors and a shade of blue was needed.   White or yellow shows up quite well against black.

You can change the color (COLOR_TITLE) in color.h easily, but I'll try some colors with more contrast.

Also, any plans to implement the FET Rds-on and body diode Vf measurements that 1.12k does?

I'll put it on the to-do list. With R_DS_on we have to be careful because the tester is limited to 5V, i.e. max. V_GS is 5V.

[madires]

Whether it is possible to make in your firmware the same mode of the continuous measurements, how at Karl-Heinz?
That is, that the display wasn't cleared every time in case of new measurement, and only the tested value changed?

Do you mean the "resistor meter" and "capacitor meter" menu functions?

[indman]

Yes, madires, i mean LCR measurement mode - the capacitor, inductor, resistance.
At Karl - Heinz it is most conveniently organized.

[texaspyro]

With R_DS_on we have to be careful because the tester is limited to 5V, i.e. max. V_GS is 5V.

At the low channel currents used by the tester,  5V for Vgs will give a pretty good idea of the Rds of most FETs (even those that are spec'd for a 10+ volt Vgs... certainly good enough for sorting through devices.   Testing some high threshold devices with 1.12K was showing an Rds of 100 milliohms.   Checking them with 15 volts on the gate, an HP3458A showed a channel resistance of 95 milliohms.

Being able to check devices at sub-threshold gate voltage can be useful.  I built a 20,000 capacitive discharge amp spot welder with 18 IRFP2907's in parallel.  I bought 100 fets and matched them by comparing their channel resistance at Vgs=3V  I wanted the devices to turn on at the same time and chose those that were closest.  At 3V the 100 devices had Rds values from 30 to 3000 milliohms.

[chick0n]

no, your not fast enough.
you short the 3 pins together, then turn it on.
it says "self test?" and you press the button quickly to go into calibration mode.

the only other time i have seen it constantly say it's not calibrated is when the eeprom was not programmed properly.

hmm...avrdude verifies the eeprom ok

[chick0n]

no, your not fast enough.
you short the 3 pins together, then turn it on.
it says "self test?" and you press the button quickly to go into calibration mode.

the only other time i have seen it constantly say it's not calibrated is when the eeprom was not programmed properly.

Ok... I think I figured it out.

I think the Button of my Tester, is somehow connected to PC6 (Reset Pin) instead of PD7.


"Pauli" here, had the same Problem:
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/250/

He Connected his Button to PC6, and wondered why his Tester didn`t react to Pressed Button after "Selftest?" question.

Can I Correct this in the Source-Code, or do I have to make Hardware-Modification?

Thanks!

[chick0n]

no, your not fast enough.
you short the 3 pins together, then turn it on.
it says "self test?" and you press the button quickly to go into calibration mode.

the only other time i have seen it constantly say it's not calibrated is when the eeprom was not programmed properly.

Ok... I think I figured it out.

I think the Button of my Tester, is somehow connected to PC6 (Reset Pin) instead of PD7.


"Pauli" here, had the same Problem:
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/250/

He Connected his Button to PC6, and wondered why his Tester didn`t react to Pressed Button after "Selftest?" question.

Can I Correct this in the Source-Code, or do I have to make Hardware-Modification?

Thanks!

I measured it, and the button is connected to PD0. (What the heck??)

So I soldered a bridge from PD0 to PD7. Now everything Works.....

Better DONT buy this clone:
http://www.banggood.com/DIY-M328-Transistor-Tester-LCR-Diode-Capacitance-ESR-Meter-p-1056454.html

[texaspyro]

One thing that I noticed is that blue text on the black background is VERY difficult to read (particularly when the sign-on / bye splash screens flash by in under a second)  Perhaps a more contrasty color would a better choice.  People had a similar issue in Lady Heather and I changed the blue to a lighter, more violet palette... it's still not all that good, but I needed to display 14 more-or-less distinct colors and a shade of blue was needed.   White or yellow shows up quite well against black.

You can change the color (COLOR_TITLE) in color.h easily, but I'll try some colors with more contrast.

Also, any plans to implement the FET Rds-on and body diode Vf measurements that 1.12k does?

I'll put it on the to-do list. With R_DS_on we have to be careful because the tester is limited to 5V, i.e. max. V_GS is 5V.

I finally got the 1.26 tar.gz file to decompress properly and compile for my 16 MHz AY-AT (using WinAVR).  I changed the title color to white and it looks good.   I also edited the display routine in user.c to show capacitance in uF...  I'm a luddite geezer and hate those new fangled nanofarad thingies...  pF and uF only for me.

My configuration uses 98.1% of the flash capacity...  I suspect something got to go (probably the remote control tool) if the Rds and Vf measurements are added. 

I have a 10 watt "TV-B-GONE" flashlight that sequentially sends the OFF codes for most televisions.  There are a lot of codes that the tester could not identify... not surprising... there are a LOT of remote control formats out there.

[madires]

My configuration uses 98.1% of the flash capacity...  I suspect something got to go (probably the remote control tool) if the Rds and Vf measurements are added. 

I assume that both won't increase the firmware much, because Vf is already measured by the diode check, and R_DS_on is just a simple calculation (measured values are already available also). No biggy

I have a 10 watt "TV-B-GONE" flashlight that sequentially sends the OFF codes for most televisions.  There are a lot of codes that the tester could not identify... not surprising... there are a LOT of remote control formats out there.

Yup, tons of IR protocols. If you're interested in IR codes, there are a few web sites with lists or databases of IR codes. I've included the most common ones from the remote controls I've borrowed from my family and a few neighbours. IIRC, about the half uses the NEC protocol, expecially unknown brands.

[upsss]

How low can they go?  <$5.77 shipped?

https://www.aliexpress.com/item/LCR-T4-Transistor-Tester-12846-LCD-M328-Tester-Newest-Diode-Triode-Capacitance-ESR-Meter-MOS-PNP/32721881253.html

Need a case?  $2.70

https://www.aliexpress.com/item/Diode-Triode-Capacitance-ESR-Meter-MOS-PNP-LCR-T4-Transistor-Tester-LCD-Display-Mega328-Transistors-Diodes/32765181716.html?

[AlxDroidDev]

I have a 10 watt "TV-B-GONE" flashlight that sequentially sends the OFF codes for most televisions.  There are a lot of codes that the tester could not identify... not surprising... there are a LOT of remote control formats out there.

Writing an Arduino sketch and schematics that receives IR codes and prints them on a LCD display isn't complicated at all. Let me me know if you want something like that.

Actually, the code that receives the IR data and prints it on a serial terminal is already as a sample in the IRremote library (by Ken Shirriff). It is the IRrecvDump sample and can be built on a breadboard.

[texaspyro]

I've done a lot of IR decoding / sending before.   The 10 watt TV-B-GONE flashlight will turn off TV's from a LONG way away.  I had it in my jacket pocket when I was in a hobby store that had a couple dozen TVs running... I switched it on, still in my pocket,  they all went off within 30 seconds. 

I was just using it to play with the tester IR decoder function.   I think it sends around 50 different OFF codes in sequence.  The IR function is cute, but I'm not sure how useful it is.  If I don't run out of space, it will stay. 

[deriterkeeg]

How low can they go?  <$5.77 shipped?

https://www.aliexpress.com/item/LCR-T4-Transistor-Tester-12846-LCD-M328-Tester-Newest-Diode-Triode-Capacitance-ESR-Meter-MOS-PNP/32721881253.html

Hi,
Thanks for the links but .... please read again bullet #5:
"5. 1602 lcd display uses LCD (12864 LCD with backlight) "
The pictures are exhibiting a graphic LCD ! !.

By the way, Thanks to all the contributors, especially to Madires.
regards

[hapless]

Something tells me that whoever posted that doesn't really know what it means. Correct me if I'm wrong, but I'd say it's either 1602 or 12864, not both. The picture is probably (probably!) a better indication of what's actually for sale.

[upsss]

How low can they go?  <$5.77 shipped?

https://www.aliexpress.com/item/LCR-T4-Transistor-Tester-12846-LCD-M328-Tester-Newest-Diode-Triode-Capacitance-ESR-Meter-MOS-PNP/32721881253.html

Hi,
Thanks for the links but .... please read again bullet #5:
"5. 1602 lcd display uses LCD (12864 LCD with backlight) "
The pictures are exhibiting a graphic LCD ! !.

By the way, Thanks to all the contributors, especially to Madires.
regards

This is one of the original $20 "LCR T4" versions and probably half of the people here purchased one of these over the years.  This is what I have done with mine, including replacing the 8MHz crystal with a 16MHz one.

[stj]

what is the relay for?

[upsss]

The relay DPDT is normally closed and it shorts all input, when you turn on the tester the relay opens.  Basically the relay protect all inputs if you insert a charged capacitor.