$20 LCR ESR Transistor checker project

[Per Hansson]

Karl-Heinz and I are sometimes amazed what can be achieved with that simple circuit.

Correction: there are allot more people that are amazed and talk about it, myself included!

[Feliciano]

Dears,

Please give me a hand with my TC-1: I replaced U4 with a circuit composed of a veroboard and 2N3906, 2N3904, 3K3, 24K, 1N4148 (the small parts that I had at hand) plus enameled wire. Then I soldered a reversed SPI and flashed an 1.44m, make'd following the Clones file. Note: for the ST7735 I disabled the SPI_hardware (as I've read the pin assignment of this doesn't allow that), and added the spi bitbang configuration which was not on that section of the config_644.h. My flash size was 99.7% of the max.

At rest, it draws 4uA (as expected), and U4_P1 is Vbatt (3.8V), the rest 0V. If I short-press the button, the screen goes white for a second, then goes totally black with the backlight still on, drawing around 200mA, the button no longer responds and I have to remove the battery to power it off. If I long-press the button, the screen remains white for two or three seconds and then the same. When on, I measure close to 5V on the U4 pads.

Has anybody had similar difficulties?

BTW: Just in case, I'm following a schematic that sets P7(PD1) low when pressing the button, opposite to an old message in this thread during the early stages of support for this unit.

[indman]

Try pouring this firmware into the processor for a test
https://yadi.sk/d/yW8xa5NJgUo5z/LCR%20%D0%A2%D0%A1-1/Firmware/Markus%20Reschke/English/16MHz

[Feliciano]

Spasiba. Now I know my error(s) was in the firmware settings (and not the hardware mod). Your 1.34m works, although the offsets are wrong (cutted letters at the top and the right, and garbage at the bottom). I'll compare the provided config.h and config644.h with mines to see how to fix my 1.44m.

Edit: Fixed my 1.44m. Thanks again, indman 

[Vitaly_Ne]

Added to the menu - Voltage.....

Yury_K, do not tell me in which file what to fix, so that some colors can be changed?
in particular, I would like to make the colors of contacts 1,2,3 cyan, green, magenta.
I compiled the firmware from the "ST7735" folder (according to your Make-file, guided by this message), but it turned out I can only change the standard - the background color and the text color ...
Maybe where you need to register SEMI_ST7735 instead of ST7735? I can't figure out which files and what to fix yet ... I have a BGR 7735 display. Maybe at least just the names of the files, tell me which ones to dig (only those where the colors can be edited)?
Or can I write the colors of the probes in the Make-file? (although I tried to add it like this, but there is no result ... although everything was compiled without errors) ... In firmware 1.44m it is easier there (there is a file colors.h))))

[Feliciano]

As you refer, on the m-firmware there is the colors.h file, there you will find the RGB color definitions for the colors for the particular display you're about to use (if your display is BGR instead, I think the conversion is handled internally), followed by a section where you assign the particular color you want for an specific item on the screen.

You also have to uncomment the UI_PROBE_COLORS on the config.h for the zocket_terminals / cable_leads to be colored.

I attach some samples of this on 1.44m for a ST7735.

[Yuriy_K]

Yury_K, do not tell me in which file what to fix, so that some colors can be changed?
 ... In firmware 1.44m it is easier there (there is a file colors.h))))

Want to change colors? Try it out on m firmware. If possible, transfer his approach to the sources from Karl-Heinz. It took me over two years to do this. There is not enough room on the 328 processor without removing some of the Karl-Heinz approaches to colors.

[Vitaly_Ne]

...I attach some samples of this on 1.44m for a ST7735...

Yes, at 1.44m I know all this and there are no problems, everything works out there )))

...Want to change colors? Try it out on m firmware. If possible, transfer his approach to the sources from Karl-Heinz. It took me over two years to do this. There is not enough room on the 328 processor without removing some of the Karl-Heinz approaches to colors.

It's clear. It is really difficult to deal with colors on k-firmware.
I looked more closely at the instructions, it says directly that at the moment the chromaticity is not used ... only the general background color and the text color can be changed.

Thanks for answers. In general, the situation has cleared up)))

[Dumidan]

Question for madires: can the measuring range of capacitors be extended to supercapacitors?

I think it would be useful to be able to check the value of supercapacitors, even with lower accuracy, like 5% - 10%.

For example, I want to know if a supercapacitor of 0.33F/5.5V is still good, ie if it has a value close to the one inscribed on it. I'm not necessarily interested in ESR or power leakage.

[madires]

Sorry, supercaps can't be checked with the Transistortester because they require a special test setup with a constant current discharge. Neither can a typical LCR meter, e.g. DE-5000, measure them.

[Dumidan]

So a measurement solution would be a separate assembly, which measures the charging time with a constant current, a process controlled by an MCU.

Yeah, I'll get to work.

OK, thanks for the quick response and for the idea.

[madires]

The steps for measuring the capacitance of a supercap are:
- charge the supercap
- start discharging the supercap via a constant current (I)
- a little bit later: measure the cap's voltage (V1) and start counting seconds (T1)
- some time later: take a second voltage measurement (V2) and get the time elapsed since the first measurement (T2 - T1)
- C = I (T2 - T1) / (V1 - V2)

[Vitaly_Ne]

Hello.
There is no "transistor" item in the menu (firmware 1.44m) ... it only measures if you initially insert and apply power.
If you work constantly through the "Menu" and you need to measure the transistor, then you have to press "Exit", then again after the inscription "Done!" (she's also annoying, it's better to have a blank screen ) ... or to turn on / off the power, which is not very convenient.
Is it possible to add a separate item?Something like an "RCL-monitor" ... like a "TD-monitor" (Transistor-Diode)? Or just a "Transistor" (like in firmware 1.13k for example) ...
Not fundamentally, of course, but for convenience...

[Feliciano]

Going back to the colors subject, I have a question or feature request:
Would it be possible to reverse the color of some numbers, i.e. color squares with white numbers for the symbols and titles?
I think for some screens&colors combinations that would be easier to read.

[indman]

Feliciano, all this can be made multicolored and inverse, but take into account that this will increase the memory consumption for the firmware, which is already catastrophically not enough for ATmega328(324)!

[madires]

There is no "transistor" item in the menu (firmware 1.44m) ... it only measures if you initially insert and apply power.
If you work constantly through the "Menu" and you need to measure the transistor, then you have to press "Exit", then again after the inscription "Done!" (she's also annoying, it's better to have a blank screen ) ... or to turn on / off the power, which is not very convenient.
Is it possible to add a separate item?Something like an "RCL-monitor" ... like a "TD-monitor" (Transistor-Diode)? Or just a "Transistor" (like in firmware 1.13k for example) ...

Should be possible. But it would be something for an ATmega with 64kB flash.

[Feliciano]

Feliciano, all this can be made multicolored and inverse, but take into account that this will increase the memory consumption for the firmware, which is already catastrophically not enough for ATmega328(324)!

That's what I was afraid of. Anyways I think it would be a good option for 64KB units.

[indman]

Yes,for devices with 64kb or more memory there is an opportunity to add color coloring and big symbols, but then largely lost the versatility of basic firmware, which can not give up our esteemed authors.

[Vitaly_Ne]

Should be possible. But it would be something for an ATmega with 64kB flash.

Yes, memory problems are serious, alas.
But on the other hand, there is an option to disable unused menu items.
For example, I have never used (10-PWM, generator, frequency counter) at all ... and if you suddenly need it sometime, then it's a matter of 15 minutes to recompile the firmware by replacing something ...
It's just good when there is a large selection of items and the user can rebuild according to his needs (taking into account the memory of course)

[madires]

I'll put it on the to-do list (low priority). BTW, I've started working on the ring tester.

[Feliciano]

if you suddenly need it sometime, then it's a matter of 15 minutes to recompile the firmware by replacing something ...

Yes, because memory limitations everyone should prioritize which functions use often and which functions are seldom used. To recompile it's an option, other is to have two (or three) devices ready-made for different purposes.

I'll put it on the to-do list (low priority).

Good (no rush indeed). I was thinking one approach to keep memory consumption under control could be to tweak the font file. For instance, AFAIK in English the letters Ä,Ö,Ü,ä,ö,ü are not used. That could give us 6 places where to put the reversed numbers. Other special characters that could be revised are the three quotes on the font file, i.e. ´,', " and the ~ (which I don't recall whether it's currently used by the firmware), as well as the round, square and curly brackets. I attach a font sample to help you ponder whether this approach could be implemented (and of benefit). Of course the other apprach would it be to set the background for a tile in one color and the foreground in other. I don't know which method would use more flash, so I leave it to the expert (madires).

[Vitaly_Ne]

...BTW, I've started working on the ring tester.

"ring tester"(oh, this google ...) Those. I understand correctly that you are planning to make a function to ring out radio components?

[madires]

I was thinking one approach to keep memory consumption under control could be to tweak the font file. For instance, AFAIK in English the letters Ä,Ö,Ü,ä,ö,ü are not used. That could give us 6 places where to put the reversed numbers. Other special characters that could be revised are the three quotes on the font file, i.e. ´,', " and the ~ (which I don't recall whether it's currently used by the firmware), as well as the round, square and curly brackets.

Of course you can remove unused characters and lower the flash usage, but it will become a nightmare to maintain font files specific for each language.

[madires]

"ring tester"(oh, this google ...) Those. I understand correctly that you are planning to make a function to ring out radio components?

Also called LOPT or FBT tester. It's meant to check chokes and transformers for shorts.

[indman]

"ring tester"(oh, this google ...) Those. I understand correctly that you are planning to make a function to ring out radio components?

And it's not a bad idea to add an audible continuity check and sound notification of the p-n junction of diodes and transistors?