$20 LCR ESR Transistor checker project

[JonnieCache]

I'm diving into the LCR fray here. I haven't read all 182 pages, but I have read the past 25 or so. It sounds like the AY-AT board with the rotary encoder is the one to get at the moment. Thanks especially to madires for all his work on this project! It is truly amazing!

I'm fairly new to electronics mods although I have built many projects over the years. I apologize if these questions are so basic.

I want to run the M-firmware, so it looks like I need to make the mods shown here: https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg1286025/#msg1286025

My questions are these:

1. The AY-AT kits that I'm seeing don't have the IR sensor. It's not that I really NEED that, but it would be cool to have. Is there a way to add the IR to that board?

2. The kits that I'm seeing come with a monochrome LCD display. Is it possible to swap out for a color LCD/OLED or is that not recommended at this time? If color is okay to use, which display is best for this application? The ILI9341?

3. I can't tell what ATMega chips are coming with the kits that I'm finding. It looks like maybe a 328P The posted specs are rather limited. Do I need to worry about this? What is the most recommended chip at this time?

4. Likewise, I can't tell what crystal comes with the kits. Is it simply a matter of swapping out for a 20Mhz? The ATMega won't mind? I'm guessing not since the specs at http://www.microchip.com/wwwproducts/en/ATmega328p indicate that it supports 20Mhz. Just want to make sure.

Thanks in advance for any assistance!

J

[Willem52]

Is this all the stuff I need to start programming the chip???

Could I ask you for the links to these, please?

Example for 10 pin to 6 pin adapter:
https://www.aliexpress.com/item/10-Pin-to-6-Pin-Adapter-Board-for-AVRISP-MKII-USBASP-STK500-High-Quality/32843191858.html

Example for USBASP v2.0:
https://www.aliexpress.com/item/1pcs-Free-shipping-USB-ISP-USBasp-USBisp-Programmer-for-51-ATMEL-AVR-download-support-Win-7/32702960733.html

Example AVR development board:
https://www.aliexpress.com/item/1pcs-ATMEGA8-ATMEGA48-ATMEGA88-Development-Board-AVR-NO-Chip-DIY-Kit/32342493690.html

or
https://www.aliexpress.com/item/AVR-ATMEGA16-Minimum-System-Board-ATmega32-USB-ISP-USBasp-Programmer/32728737348.html

[madires]

I want to run the M-firmware, so it looks like I need to make the mods shown here: https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg1286025/#msg1286025

You don't have to mod the AY-AT, but the mod will improve the tester for just a few bucks.

1. The AY-AT kits that I'm seeing don't have the IR sensor. It's not that I really NEED that, but it would be cool to have. Is there a way to add the IR to that board?

Simply start the IR decoder and connect the IR receiver module to the three probe pins.

2. The kits that I'm seeing come with a monochrome LCD display. Is it possible to swap out for a color LCD/OLED or is that not recommended at this time? If color is okay to use, which display is best for this application? The ILI9341?

If you prefer a large screen the ILI9341/9342, otherwise the ST7735 or ILI9163.

3. I can't tell what ATMega chips are coming with the kits that I'm finding. It looks like maybe a 328P The posted specs are rather limited. Do I need to worry about this? What is the most recommended chip at this time?

Yes, it's an ATmega328. There aren't any clones with ATmega644/1284 to buy yet, i.e. you would have to build one yourself. If you enable all features the 328 will be maxed out. And there are also some hardware options which require the additional I/O pins of a 644/1284.

4. Likewise, I can't tell what crystal comes with the kits. Is it simply a matter of swapping out for a 20Mhz? The ATMega won't mind? I'm guessing not since the specs at http://www.microchip.com/wwwproducts/en/ATmega328p indicate that it supports 20Mhz. Just want to make sure.

It comes with an 8 MHz crystal, IIRC. I'd recommend the 16 MHz crystal because it will allow you to run both firmwares (k & m).

[JonnieCache]

I want to run the M-firmware, so it looks like I need to make the mods shown here: https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg1286025/#msg1286025

You don't have to mod the AY-AT, but the mod will improve the tester for just a few bucks.

1. The AY-AT kits that I'm seeing don't have the IR sensor. It's not that I really NEED that, but it would be cool to have. Is there a way to add the IR to that board?

Simply start the IR decoder and connect the IR receiver module to the three probe pins.

2. The kits that I'm seeing come with a monochrome LCD display. Is it possible to swap out for a color LCD/OLED or is that not recommended at this time? If color is okay to use, which display is best for this application? The ILI9341?

If you prefer a large screen the ILI9341/9342, otherwise the ST7735 or ILI9163.

3. I can't tell what ATMega chips are coming with the kits that I'm finding. It looks like maybe a 328P The posted specs are rather limited. Do I need to worry about this? What is the most recommended chip at this time?

Yes, it's an ATmega328. There aren't any clones with ATmega644/1284 to buy yet, i.e. you would have to build one yourself. If you enable all features the 328 will be maxed out. And there are also some hardware options which require the additional I/O pins of a 644/1284.

4. Likewise, I can't tell what crystal comes with the kits. Is it simply a matter of swapping out for a 20Mhz? The ATMega won't mind? I'm guessing not since the specs at http://www.microchip.com/wwwproducts/en/ATmega328p indicate that it supports 20Mhz. Just want to make sure.

It comes with an 8 MHz crystal, IIRC. I'd recommend the 16 MHz crystal because it will allow you to run both firmwares (k & m).

Thank you for all the advice, madires!

It looks like the ILI9341/9342 will be too big to stay in keeping with the original design. Do you know if there are pinouts published for the AY-AT board? I want to make sure that the ST7735 or ILI9163 board that I purchase will be compatible.

I think the rest of your information has me all sorted! Thanks!

[madires]

jakeisprobably has posted a link to his AY-AT circuit diagram which includes also the mods.

Edit: Found the link: https://github.com/Upcycle-Electronics/AVR-Transistor-Tester

[perdrix]

Hi

Are there any ATMega644/1284 board designs yet?

Dave

[madires]

Yes For example: https://drive.google.com/drive/folders/0B4yqyYy2DaakQjNmZ3NUTG1YcVU

[perdrix]

Thanks

Could you point to any discussions about that version?

Dave

[madires]

It's the circuit depicted in Karl-Heinz's documentation. I haven't seen any discussions about that circuit here but maybe you'll find more information in the Russian forum http://vrtp.ru/index.php?showtopic=16451.

[sk760]

HI, i have an multifunction tester TC1 but is with Atmega324P not Atmega328
Can help someone with firmware for this tester?

Thank you.

[Per Hansson]

I wrote that on K software my tester works but thats not true, after some time it displays message "uncalibrated"

I found this information in documentation of k software:
At this place I will give you an additional important hint. Never do a measurement with connected ISP plug!
The ISP interface influences the measurement.

Could it be that the programming cables cause the issues with your software too? By the cables I mean about 4cm long from microcontroller to 6 pin isp plug. The cables are lying on the pcb.

The reason is that three pins of the MCU are shared between ISP and probe/test resistors. The length of the traces (and wires in your case) should be kept as short as possible, and the layout should keep the traces away from noisy stuff. I don't think a few centimeters are a problem. More likely the wires are picking up some signal from another trace/wire. A few mV can already screw up the ESR measurement.

Hi Madires, can I just follow on with a question here, don't know if you saw my linked post below already.
Anyway I got that relay I was thinking of using to switch out the ISP leads, but would you say that would not work well anyway then?
Reason I have not tried it is because it was a bit bigger than what I understood from the specs so I would have to cut the case a bit...
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg1387441/#msg1387441

[madires]

HI, i have an multifunction tester TC1 but is with Atmega324P not Atmega328
Can help someone with firmware for this tester?

The ATmega324 is supported by k and m-firmware but the TC-1 has an additional ATtiny for controlling some signals. Someone would have to reverse engineer that ATtiny. Another issue with the TC-1 is the poor pin assignment. By swapping two pins the circuit could support hardware SPI.

[madires]

Hi Madires, can I just follow on with a question here, don't know if you saw my linked post below already.
Anyway I got that relay I was thinking of using to switch out the ISP leads, but would you say that would not work well anyway then?
Reason I have not tried it is because it was a bit bigger than what I understood from the specs so I would have to cut the case a bit...
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg1387441/#msg1387441

If you keep the wires between the ISP and the relay short it might work fine. Give it a try. And I'd wait with the modification of the case, just in case

[sk760]

Thank Madires for your response.
i reflash Atmega witk K and m firmware but LCD is White screen,you know if Attiny is problem for my case,or you cand give me an correct firmware...
Maybe can learn me how i can do this swapping.

HI, i have an multifunction tester TC1 but is with Atmega324P not Atmega328
Can help someone with firmware for this tester?

The ATmega324 is supported by k and m-firmware but the TC-1 has an additional ATtiny for controlling some signals. Someone would have to reverse engineer that ATtiny. Another issue with the TC-1 is the poor pin assignment. By swapping two pins the circuit could support hardware SPI.

[madires]

The function of the ATtiny has to be figured out first before we are able to change the firmware configuration to cope with that. Maybe some firmware changes are required too. The two pins need to be swapped in the PCB layout (hardwired function in the MCU).

[indman]

Hi, Madires!
I'm sorry!I apologize that incorrectly I gave information on the diagram LCR-TC-1.
One of owners of this instrument read marking of this chip of U4.
It is the STC15L104W controller. I put the corrected diagram to my message.
The main problem in testing of a firmware for this clone is that I have no it in hands!
Now about problems with M-Firmware.
1. The image was turned. I turned it in the necessary side. But at the edges of the display the noise strip is visible and also the picture is shifted on several pixels to the left and up. Fish8840TFT clone has the same problem and with the same Z180SN009 display. What you can advise for correction of this error? Reduction of resolution of the display to 124x156 does not correct a problem.

[madires]

IIRC, the Z180SN009 is based on the ST7735S. That controller supports up to 132x162 dots but the LCDs are 128x160 usually. A 128x160 LCD module could be wired starting at different addresses. Additionally the ST7735S has three pins for setting the LCD's resolution to either 132x162 or 128x160 which implies a specific wiring offset (moved to the mid). Maybe there are 128x160 modules wired starting at 1x1 but set to 132x162. When directions are flipped we'd get offset problems. So we need an option to shift x and y by the module specific offsets to cope with all the possible variations. And there's still the issue with the additional MCU controlling some important signals. Does anyone like to sponsor a TC-1 for reverse engineering and testing?

[pol098]

Has anybody thought of using this type of tester for testing the ESR of batteries? I haven't found any mention of this in the forum (maybe I missed it) or the documentation. This gives a very useful indication of state of charge of disposable batteries, and of condition (wear) of rechargeable batteries. I have a Bob Parker ESR meter intended for use with capacitors, but with circuitry that allows low-voltage batteries to be connected without harm. I use it to test the state of alkaline cells; it's also said to be useful for estimating the wear on LiIon batteries, which I can't yet confirm. The reports I've seen of damaging the $20 tester by connecting a charged capacitor make me leery of trying to test batteries with it (I don't yet have one).

ESR of alkaline batteries varies to some extent with manufacturer, as well as type; it's best to record the ESR of new batteries of the types you use. For example, for the alkaline AA batteries I use, the measuring technique of the Bob Parker meter reads around 0.12 ohm for a new one; depending upon the application 0.3 ohm upwards is time to change. This is very much not an exact science, but useful conclusions can be drawn. Possibly batteries could be safely tested with a low-ESR blocking capacitor in series?

[madires]

The tester's standard circuit can't measure the ESR of a battery. However, it's possible to design a hardware option to do that (load method?).

[mebel]

Where can I set cpu frequency in m software? I can not find it.

[madires]

In the Makefile.

[RGK]

Do I understand correctly that if I build an "AY-AT" kit with all the supplied cheapo parts and substitute the high-grade parts jakeisprobably listed in post #3893, minus the 20MHz crystal, that the unit should power on run properly without updating the firmware?

BK

[madires]

Yep, as long as you keep the 8MHz crystal. If you change the crystal the tester will still power on but the timing for several functions and measurements will be wrong.

[RGK]

Excellent - thanks for the quick reply/confirmation.

BK

[RGK]

Mouser is backordered on the MCP1702-5002E/TO part.  Any suitable alternates?

BK