$20 LCR ESR Transistor checker project

[madires]

I see. In this case replace the ATmega or get a new tester.

[blubillcanada]

I wonder how hard this project would be to port over to a Raspberry Pi Pico.
USB would make for a simple display on a PC to keep it real simple, also firmware updates would be a snap.
A significant increase in the program memory 2MB vs 32kB, more speed! & cheap too.
It can be programmed in C++ or Python
The ADC VREF is easy, LM4040 is recommended in the Pico datasheet.
pushbutton(s), 470K,  680ohm resistors and a connector would be all the external parts for a basic unit.
Optionally:

• an LCD / OLED display as is tradition (personally I like the no display terminal option as I have a PC on my workbench)
  
• keypad or rotary switch

The original tester schematic just for reference.

[madires]

That was answered already just two pages back: https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg4318561/#msg4318561
The Raspberry Pi Pico has the same drawback, it runs with 3.3V.

[n6rob]

I have no idea what version that is, but trying a OCR translation it seems to be saying that the USB port is only for user upgrades (of the firmware) and that it does not supply power.

Then it should be possible to update the firmware directly via avrdude.

Do you have any suggestions for how to set avrdude (in Linux command line)?  I'm not sure how to set the "-c" switch (i.e. which programmer) as I am connecting my computer USB directly to the USBC connector on the board.

~$ lsusb
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 046d:c534 Logitech, Inc. Unifying Receiver
Bus 001 Device 019: ID 1a86:7523 QinHeng Electronics CH340 serial converter
Bus 001 Device 002: ID 05e3:0608 Genesys Logic, Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

I tried this...

~$ avrdude -c ttl232r -p m328p
avrdude: ft245r_open(): invalid device identifier '        '

avrdude done.  Thank you.

[madires]

Adding the port argument might help, e.g. -P /dev/ttyACM0. But I don't know which programmer needs to be set for the CH340.

[n6rob]

Adding the port argument might help, e.g. -P /dev/ttyACM0. But I don't know which programmer needs to be set for the CH340.

Okay.  I played around with a few port designations and programmer options but was never successful. 

I wrote to the seller asking for instructions and a schematic.  They replied and said they were working on getting me the info.  If I learn anything I will share it here.

Thanks for the help.

[carrascoso]

Hello everyone.
I like to try out the different options Madires adds to our little meter.
The last thing was the continuity meter that is already working thanks to the help of Indman.

Now I have assembled the circuit for the LOPT/FBT measurement but it does not work.
I have reviewed the assembled circuit and in principle it is fine, but it does not go beyond screen 1, both with or without the coil being tested.
It always emits a small constant and intermittent sound.

Perhaps, as in the case of continuity, some other adjustment must be made or activated.
Please if someone can help me to solve the problem.

Thank you

 

[madires]

Could you please post your settings for the ring tester? Do you have a scope to check the trigger pulse and the rings?

[carrascoso]

Could you please post your settings for the ring tester? Do you have a scope to check the trigger pulse and the rings?

[madires]

And the settings for RINGTESTER_PORT, RINGTESTER_DDR and RINGTESTER_OUT? Is the port pin set in RINGTESTER_OUT used by any other setting too?

[carrascoso]

The three that you tell me are activated

[madires]

You have
 #define RINGTESTER_OUT   PD5       /* pulse output */
and
 #define BUZZER_CTRL      PD5       /* control pin (low: off / high: on) */
while
 #define HW_RING_TESTER
and
 #define HW_BUZZER

So ring tester and buzzer are enabled and are using the same port pin. Try another pin or disable the buzzer (also remove the buzzer).

[Yuriy_K]

Information for users of my firmware. The reaction to a short-circuited coil is shown in the pictures on the right.

[indman]

The reaction to a short-circuited coil is shown in the pictures on the right.

This method does not guarantee 100% detection of short-circuited coil.Example in the photo below. You should always have a sample of a similar, serviceable throttle to compare readings. The simplified version of LOPT/FBT also cannot guarantee accurate detection of short-circuited turns and is very dependent on the core material. It is better to use specialized devices for this purpose.

[masster]

Does anyone have the schematic for the tester clone known as Kuman Multifunction Transistor Checker or DROK Transistor tester?
https://www.amazon.com/kuman-Multifunction-Transistor-Automatic-Identification/dp/B075DDXV11
http://www.kumantech.com/kuman-multifunction-transistor-tester-with-18-inch-lcd-tft-display-mega328-npn-pnp-automatic-identification-transistor-diodes-dual-diode-scr-res_p0435.html

[indman]

masster Look at my resource https://disk.yandex.ru/d/yW8xa5NJgUo5z the "Fish8840TFT" folder

[firewalker]

masster Look at my resource https://disk.yandex.ru/d/yW8xa5NJgUo5z the "Fish8840TFT" folder

The folder with the MK-328 is the firmware the device came with?

Alexander.

[indman]

firewalker No, if there is a factory firmware, it will be located in the "Firmware/Original" folder

Hi,
I know there are a lot of different models, anyway have you saw this one ?
What is the purpose of USB interface ?
I try to use it to supply the module, it shows around 7 V, but didn't measure a simple resistor.

https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg4291063/#msg4291063

Surprises from Chinese friends continue!
This clone of T4 is not based on the original ATmega328, but so far on a processor known only to FNIRSI.
The marking on the ATMega328PU-TH case is a fake, since the pins of this chip does not match either ATMel or LGT8F328P.
The K2 button is used to enter BootLoader mode.

[masster]

Quote from: indman on Yesterday at 11:53:56 pm>masster Look at my resource https://disk.yandex.ru/d/yW8xa5NJgUo5z the "Fish8840TFT" folder

Quite a treasure you have there. Well organized and very full of resources.

Just a short observation though. On the schematic it is missing the LED between R6 and Q3.


I am confronting myself with the following problem: while the tester is working fine, when I press the TEST button, the current consumption is 220 mA (!!) and the battery voltage is reported wrong (7.72V instead of 8.9V). Transistor Q1 gets very hot. Alcohol evaporates almost instantly on it, in comparison with the other components. If I supply 6V instead of 9V, the current consumption drops to about 70mA, still too much IMO. Could it be a faulty capacitor C1?

[indman]

Just a short observation though. On the schematic it is missing the LED between R6 and Q3.

Yes, thank you, I will supplement the scheme with this missing element, which plays an important role in the scheme.

I am confronting myself with the following problem: while the tester is working fine, when I press the TEST button, the current consumption is 220 mA (!!) and the battery voltage is reported wrong (7.72V instead of 8.9V). Transistor Q1 gets very hot. Alcohol evaporates almost instantly on it, in comparison with the other components. If I supply 6V instead of 9V, the current consumption drops to about 70mA, still too much IMO. Could it be a faulty capacitor C1?

This is already a known unpleasant problem for this clone. Look carefully at the picture I attached below and everything will become clear to you. Instead of a 3.3V Zener, a 3.3 volt stabilizer should be installed in the sot-23 to power the TFT screen, and the board is divorced incorrectly.2 and 3 outputs shorts are connected on the board. Drawn in red. Tracks need to be cut. In fact, there is a zener diode directly parallel to the output of the 7805. VCC instead of five sinks to 4 volts, and wild consumption from the battery. In the absence of stabilizers in sot-23, I put 1117-3.3 in sot-223, it is better to leave the resistor in front of the TFT screen at one 100 ohms, but you only need to solder it from the seat, it goes straight to 5 volts.

[masster]

@indman
1) Is the schematic attached the correct one? I mean, having all the corrections already applied?
2) Resistors R3 and R5 are 33K. Shouldn't be R3=10K and R5=3K3 to show the correct value of the battery voltage?
3) I have attached a high resolution photo of my board. Can you draw on it again, please? Because the other photo is low resolution, and I can't see exactly what to cut and what to connect.

[indman]

1. Yes, the scheme is correct.
2. You can change the resistors R3-R5 if you want to use new k and m-firmware. Or compile the firmware for the divider 33k/33k yourself.
3. I showed in the photo which jumper should be removed.

[free_electron]

has anyone ported this to a 329 or 629 ? how much code would need to change ?

[madires]

I'm not aware of anyone. No idea! If the 329 is basically a 328 plus additional features, then it should be just some minor adaptions.

[Feliciano]

Appart from being on a 64pin case, the main features of the 329pa look similar to those of 328pb. Attached a quick comparison.