$20 LCR ESR Transistor checker project

[madires]

1. Is it possible to type text with 1 px offset from all edges? If I define a global offset, that line is not cleared at all and displays garbage.

You could modify the display driver to do that. However, it would be only possible for display controllers supporting address windows, but no for controllers with pages (8 bits heigh addressing bars).

2. Can small fonts (8x8) be upscaled twice vertically without losing flash space?

That should be feasible with a driver modification (see LCD_Symbol() of a driver supporting SYMBOL_RESIZE).

[tofof]

What is the current consensus on the better chip for this project, a 324 or a 328? I have contacted many vendors of the T2 through ebay requesting board photos, to see if any of them do indeed have a genuine 324 inside as a few posters have managed to luck into. Alternatively, the german Joy-It T7 seems to be a safe way of getting a 328.

Is there any compelling advantage of one of these chips over the other?

[madires]

The ATmega324 has more I/O pins which is great for addtional hardware options and driving a display via hardware SPI. Unfortunately, the pin assignment of tester clones is regularly screwed up and you won't get hardware SPI without some modifications.

[Jacon]

Hi Marcus & T-Checkers,

Attached please find updated Polish translation file 
Good for discovering photovoltaic effect in various elements 

[TankedThomas]

Since there's the WIP firmware for this chip

What firmware, which is tested and fully functional, are you going to program into the LGT8F328 chip?
My advice - do not waste your time, but change the chip to a classic ATMega328, for which there are author's working firmware.

I don't believe it's fully functional nor up-to-date, but this is the firmware I was thinking of: https://github.com/DurandA/transistor-tester-lgt328p

To be honest, I don't think I have the skills to remove and solder SMD chips. My eyesight isn't great (though I do have a microscope I can use) and I don't currently have rework equipment, though I do plan to get a hot air gun for it soon.

I agree with indman. At this point in time I think it will be far easier to replace the LGT8F328 with an Atmel ATmega328P. The required PC board modification is relatively simple.

I obtained a quantity of LGT8F328 "Arduino compatible" boards. These boards resemble the Arduino Pro-mini. They come with a bootloader installed and are programmed with a standard USB-TTL adaptor. I was curious to see what they are like. So far I succeeded at programming them after installing the LGT8F328 "boards" package into the Arduino IDE. These boards will run many standard Arduino sketches (such as "blink").

But I think it will still require considerable time and effort to modify existing Transistor Tester software for the LGT8F328.   

I'm not sure how to make the modifications required to swap the chips and use a full 6 pin header though - maybe the instructions are in this thread but I didn't see them when looking. If I understand correctly at least two of the pins have to be swapped.

I just have Raspbian Lite (i.e. CLI-only) installed on my main Raspberry Pi, so I don't have the full Arduino IDE to use (I do on Windows but I don't know how I'd hook the tester up to my PC), but even so, I think it's just a matter of me not knowing how to hook up the wires properly to the GPIO pins.

[Yuriy_K]

To everyone who uses my firmware. You can correctly identify JFET pins by looking at smaller Cg= readings ... Sample measurement in the picture...

[indman]

Yuriy_K,this is certainly good, but I don’t understand how knowing the correct drain and source will fundamentally change the way JFETs work, in which the channel has a symmetrical structure?

[moimem]

hello everyone
I compiled V1.50m and tried to test the DHT22 with my LCR-T4 and it was always detected as DHT11 and showed erroneous temperature and humidity so i checked the DHTxx.c code and found that it defaulted to DHT11 and i have to long-press the button twice to switch first to auto-mode then to the DHT22 sensor  which is not straightforward. i suggest 2 ways to solve this issue:
- add a submenu to select between DHT11 and DHT22
- use the fact that byte 2 and byte 4 in the DHT 11 are always 0 to make a 99% accurate guess between dth11 and dht22

[indman]

moimem,maybe the Test button works badly or unreliably?
I don't see any difficulty in the standard madires solution for picking the sensor type.

[madires]

Or you could have simply read the README file which explains the operation of the DHTxx tool?

[Maniaxx]

Is the GM328A able to test horn caps (e.g. 82V 15000uF)? I'm aware of the 5V, 7mA limit (regarding diacs, triacs) as stated in the manual but i'm not sure if this affects caps as well as the 82V is just the max voltage.

[madires]

Should be able to measure the capacitance (needs some time, be patient). I guess the ESR is going to be too low.

[Maniaxx]

Should be able to measure the capacitance (needs some time, be patient)

Still enough to figure out if its still in good shape i guess. That would be ok.

I guess the ESR is going to be too low.

You mean the on-screen ESR value not the real/technical ESR characteristics (that might lead to test abortion or sth), right?

[indman]

Is the GM328A able to test horn caps (e.g. 82V 15000uF)? I'm aware of the 5V, 7mA limit (regarding diacs, triacs) as stated in the manual but i'm not sure if this affects caps as well as the 82V is just the max voltage.

The tester is capable of measuring capacitances up to 100000uF and the model of the tester does not matter. The approximate test time for such a large capacity is 40-50 seconds.

[madires]

You mean the on-screen ESR value not the real/technical ESR characteristics (that might lead to test abortion or sth), right?

No, both. The tester's lower limit is 0.01 Ohms and anything below that will be shown as 0 Ohms. When there's a problem with the ESR measurement nothing bad happens. IIRC, the k-firmware displays 0 Ohms in that case, while the m-firmware simply doesn't show the ESR value.

[xfint34]

I checked the firmware size using the major GCC versions from GCC 12 going back to GCC 4.8.5. GCC 8.5.0 generates the smallest firmware size. A bit better than the commonly used GCC 7.3.0 for compiling these firmwares.

The results are a bit better with the m firmware. 160 bytes smaller. With k firmware it is only 26 bytes smaller.

1.50m firmware:

Code: [Select]

avr-gcc --version
avr-gcc (GCC) 7.3.0

AVR Memory Usage
----------------
Device: atmega328

Program:   27132 bytes (82.8% Full)
(.text + .data + .bootloader)

Data:        226 bytes (11.0% Full)
(.data + .bss + .noinit)

EEPROM:      749 bytes (73.1% Full)
(.eeprom)



avr-gcc --version
avr-gcc (GCC) 8.5.0

AVR Memory Usage
----------------
Device: atmega328

Program:   26972 bytes (82.3% Full)
(.text + .data + .bootloader)

Data:        226 bytes (11.0% Full)
(.data + .bss + .noinit)

EEPROM:      749 bytes (73.1% Full)
(.eeprom)


1.13k firmware:

Code: [Select]

avr-gcc --version
avr-gcc (GCC) 7.3.0

AVR Memory Usage
----------------
Device: atmega328p

Program:   31454 bytes (96.0% Full)
(.text + .data + .bootloader)

Data:        204 bytes (10.0% Full)
(.data + .bss + .noinit)

EEPROM:      875 bytes (85.4% Full)
(.eeprom)

avr-gcc --version
avr-gcc (GCC) 8.5.0

AVR Memory Usage
----------------
Device: atmega328p

Program:   31428 bytes (95.9% Full)
(.text + .data + .bootloader)

Data:        204 bytes (10.0% Full)
(.data + .bss + .noinit)

EEPROM:      875 bytes (85.4% Full)
(.eeprom)



[Maniaxx]

If the GM328A has a 16MHz crystal but the external ISP flasher dev board only an 8MHz crystal. Is it possible to flash a 16MHz firmware with an 8MHz board?
Edit: Maybe the 8MHz crystal is only used when running (not flashing) the chip on the dev board itself? The ISP pinout includes SCK (serial clock). Shouldn't that be the clock frequency (independent from crystal) provided by the ISP flasher itself?

Flasher:
https://www.aliexpress.com/item/1005001655965219.html
https://www.aliexpress.com/item/32582933115.html

[hapless]

Shouldn't make any difference.

[moimem]

Find attached simple french translation (without special letters: é è à ^¨ etc...) that work without dedicated fonts

[MaxaM]

Good morning, this is my first post although I have been following you for a long time.

I need your help: can someone kindly compile the latest firmware for GM328A (v1.50m) for 20Mhz quartz?
I am not very experienced in linux and on Windows I can't. Thank you in advance!

[Maniaxx]

can someone kindly compile the latest firmware for GM328A

If you post your configs (or the diffs) it might be possible.

[VEGETA]

hello,

i am planning to get one of these, mainly to test capacitors and their ESR.

I found this on amazon: https://www.amazon.com/Transistor-DROK-Capacitor-Capacitance-Automatic/dp/B01MS1FOYM/

is this good? also, can it be software updated? I do have pic and atmel programmer on hand.

[ledtester]

Have a look at this comparison chart:

https://github.com/madires/Transistortester-Warehouse/blob/master/Documentation/English/Clone-Comparison-Chart.pdf

Compared to other models the  one you are interested in lacks input protection and only tests zener diodes up to 5V.

It may contain a genuine Atmel MCU. Since you buying from Amazon you might be able to disassemble it, check and return it if it doesn't.

For mesuring ESR I'd take a look at the 5 transistor ESR meter project:

https://www.eevblog.com/forum/projects/5-transistor-esr-meter-design/

[VEGETA]

Have a look at this comparison chart:

https://github.com/madires/Transistortester-Warehouse/blob/master/Documentation/English/Clone-Comparison-Chart.pdf

Compared to other models the  one you are interested in lacks input protection and only tests zener diodes up to 5V.

It may contain a genuine Atmel MCU. Since you buying from Amazon you might be able to disassemble it, check and return it if it doesn't.

For mesuring ESR I'd take a look at the 5 transistor ESR meter project:

https://www.eevblog.com/forum/projects/5-transistor-esr-meter-design/

I am interested in a good form-factor thing, not bare board.

I couldn't find LCR-TC2 on amazon but found this one: https://www.amazon.com/Transistor-Aideepen-Multi-Function-Capacitor-Resistor/dp/B08YNJYWCW/

it looks like TC1 model, right?

it has "-H" variant which supposed to be upgraded specs and so on. USB power is always better than battery.

what do you think about this model?

[madires]

We can't give any recommendations on specific tester clones at the moment because many of them come with alternative MCUs and a poorly adapted firmware. Some lack the self-adjustment feature, and there are measurement issues with ESR and other values. The most important thing is to get a tester with a genuine ATmega.