$20 LCR ESR Transistor checker project

[casinada]

Timesbeing,
Google Chrome will automatically translate any page for you. It is not 100% accurate but it will give you a very good idea of what is going on.
The nice thing about the Component tester mentioned above with the AVR processor in the DIP package is that you can use a programmer such as the TL866 to reprogram it.

[avrank]

Please help me,
How to make measurements 10uh coil, can be displayed 30uH and not 0.03mH. Thanks.

Well, here goes:
1.) Do the full selftest with a 15 nF capacitor also at hand.
2.) Insert coil at 1 and 3.
3.) Insert 15 nF capacitor in parallel also at 1 and 3.
4.) Press the button.
5.) See what you get. See pic. enclosed

Yours - Messtechniker

Thank you Mr. Messetechniker

[timelessbeing]

@casinada

Yes I tried translating. It's difficult to read. I would have to browse through all the topics. It's very easy to miss something, and there may be other German sites that I'm not even aware of. I want to be sure, so I asked here. Plus, everybody else can benefit from the answer too. That's what forums are for.

> you can use a programmer such as the TL866 to reprogram it.
I don't do THAT much programming. $50 seems like a lot to spend to flash a $15 gizmo. I think there some available on eBay for a few bucks.

[tom666]

@timelessbeing

You can simply use to programming the MCU the following hardware:
- USBasp programmer (price around US $1.87)
- AVR Development Board (price around US $1.55) - or other AVR ISP adapter

Alternatively, you can use USBasp with a breadboard.

For inspiration:
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg810893/#msg810893

[timelessbeing]

Dík, Tome.
I just won an eBay auction of the USBasp programmer for $1.25 US.

[bitseeker]

Thanks. How do you flash yours, bitseeker?

I haven't reprogrammed mine yet. Instead of reflashing the original, I'm going to buy some new 328 for the newer firmware. That way I also have spares just in case I blow one up by forgetting to discharge a cap (yet another reason I chose this model, with the socketed microcontroller).

As far as programmers, there are many options, as others have posted, above. I have an Arduino Uno, which can also be used as an ISP.

e.g.,
http://www.instructables.com/id/Turn-Your-Arduino-Into-an-ISP/?ALLSTEPS

If you have to buy a programmer, try the USBasp.

[eas]

I searched online for a suitable device to buy, and this one seemed like the best option:
eBay item: 221952423890  seller: kiss_buyer  cost: 15.97 USD

Pros:

• socketed ATMega328
• 128x64 backlit graphical display with support standoffs
• Rotary encoder
• Square wave gen, PWM, frequency counter
• 8Mhz external crystal oscillator
• Very reasonable price
• Top-rated eBay seller

Cons:

• assembly required
• I don't see pads for programming the MCU in-place, which means I would need a socketed programmer like this one, right?

Did anybody else find any similar gems?

A number of us have built that one recently and been quite happy with it.

The main complaint has been that the optional case doesn't accommodate the ZIF socket provided with the PCB kit, and the socket provided with the case is sub par. I think the simplest solution I've seen posted is to stack one or two IC sockets to elevate the ZIF socket and then cut the case to accommodate it. I fitted the case with three 2mm banana sockets that I could use with test leads, or with a ZIF socket mounted on protoboard with banana plugs sticking out the bottom.

Also, some, including me, have seen corrupted characters, which is solved by flashing new firmware.

I think the lack of programming pins/pads is a bigger annoyance than it is with some of the other testers with a socketed MCU since the display is screwed down over it. I plan to bodge on some programming leads and expose a connection through the battery compartment so I can reprogram mine without having to disassemble the case and display

[hapless]

I was thinking the same thing, just add some leads to put a programming socket into the battery compartment, but what stops me from doing it is the fact that it will add some stray capacitance. With wires moving around inside the case, it will be variable and somewhat difficult to cancel out.

Cons:

• assembly required
• ...

When did this become one of the cons for an electronics hobbyist? 

[timelessbeing]

I won't bother with a case. It doesn't feel right. I do like the idea of having 2 or 4 mm sockets though. That would make it more versatile, and easy to use with existing leads.

I hadn't thought about the screen blocking the MCU. Oh well, hopefully I won't be flashing too often. I'll just see how it goes.

When did this become one of the cons for an electronics hobbyist? 

Don't get me wrong. I love building up electronics. But in this case, I would rather spend my time either using the tester to identify parts to use for my projects, or making improvements on the tester. I like the idea of a compact pre-assembled board with a low profile surface mount parts. It's going to be a hassle obtaining through hole 0.1% resistors for the probe circuit. Maybe I'll just bodge in SMCs.

[timelessbeing]

One of participants of the forum mikrocontroller.net suggested to add in makefile a line "WITH_SamplingADC = 1" that increases permission in this range to 0,01pf. Measurement needs to be done on TP1-TP3 pins.

The additional measurement for low capacitance was submitted by PA3FWM.

Is this documented somewhere? Will it be enabled by default in future version?

There will be also one for low inductance (based on a resonant circuit with a parallel known C). The problem is that the firmware with both new features ... will exceed the flash size limit of the ATmega328... we're heading to the 644/1284 to allow new features and options.

Any updates on this? I assume that upgrading won't be achieved by simply swapping the MCUs, and would require redesigning the hardware?

[madires]

The additional measurement for low capacitance was submitted by PA3FWM.

Is this documented somewhere? Will it be enabled by default in future version?

Please see Karl-Heinz' excellent documentation ( https://github.com/svn2github/transistortester/blob/master/Doku/trunk/pdftex/english/ttester.pdf ). The feature is an option and can be enabled in the Makefile of the k-firmware. Currently I have no plans for adding it to the m-firmware, because I think it's a feature for a precision bench multimeter and would require a 4 wire measurement for proper results.

There will be also one for low inductance (based on a resonant circuit with a parallel known C). The problem is that the firmware with both new features ... will exceed the flash size limit of the ATmega328... we're heading to the 644/1284 to allow new features and options.

Any updates on this? I assume that upgrading won't be achieved by simply swapping the MCUs, and would require redesigning the hardware?

The 644/1284 has a few pins more than the 328 There's a circuit in the documentation, but I don't know if that is going to be the new standard one. I think we need some discussion of the use of the additional I/O pins. It would be good to have a fixed internal SPI bus with a few /CS lines for display, touchscreen and some new option, maybe also a I2C.

[tom666]

It's going to be a hassle obtaining through hole 0.1% resistors for the probe circuit.

This DIY KIT with 128x64 G-LCD already contains 0.1% precision resistors (680 and 470k).

[eas]

I won't bother with a case. It doesn't feel right. I do like the idea of having 2 or 4 mm sockets though. That would make it more versatile, and easy to use with existing leads.

I hadn't thought about the screen blocking the MCU. Oh well, hopefully I won't be flashing too often. I'll just see how it goes.

I had a previous model without a case (or rotary encoder). I got tired of being extra careful with it.

The screen is relatively easy to remove. I don't think it would be an excessive hassle for the occasional firmware update. It probably would be if you were doing development, or in the habit of installing nightly builds.

It's going to be a hassle obtaining through hole 0.1% resistors for the probe circuit.

This DIY KIT with 128x64 G-LCD already contains 0.1% precision resistors (680 and 470k).

Ah yes, I meant to mention that. It comes with precision resistors, and, at least in my case, they were all well within spec.

[bitseeker]

It's going to be a hassle obtaining through hole 0.1% resistors for the probe circuit.

This DIY KIT with 128x64 G-LCD already contains 0.1% precision resistors (680 and 470k).

Ah yes, I meant to mention that. It comes with precision resistors, and, at least in my case, they were all well within spec.

In the kit I got, all but one was within spec (680.80?). But, the ratios still work out fine.

[bitseeker]

I searched online for a suitable device to buy, and this one seemed like the best option:
eBay item: 221952423890  seller: kiss_buyer  cost: 15.97 USD

Anyway, if you do decide to get this model, it's a good price for it. The best deal I found was a short-lived sale on Banggood at $14.93 back in September.

[timelessbeing]

Thanks for answering all my questions guys.
The hardware is on its way. I'll report back with any interesting updates.

[Intel]

Hello,

I bought the LCR-T4 version from ebay and now I'm trying to modify it to run on 18650 battery but I need to adjust battery voltage settings. I uploaded the .hex file from "mega328_T3_T4_st7565" and it seems to be working. Then I tried adjusting BAT_POOR setting and compiling, but it does not fit in size even with default makefile:

Code: [Select]

8 MHz operation configured.
AVR Memory Usage
----------------
Device: atmega328p

Program:   37102 bytes (113.2% Full)
(.text + .data + .bootloader)

Data:        464 bytes (22.7% Full)
(.data + .bss + .noinit)

EEPROM:       46 bytes (4.5% Full)
(.eeprom)
I'm using latest WinAVR (from year 2010 lol). Tried atmel gnu toolchain but it gave me errors when compiling. Any ideas why it gets so large?

Thanks

[madires]

I bought the LCR-T4 version from ebay and now I'm trying to modify it to run on 18650 battery but I need to adjust battery voltage settings. I uploaded the .hex file from "mega328_T3_T4_st7565" and it seems to be working. Then I tried adjusting BAT_POOR setting and compiling, but it does not fit in size even with default makefile:

I'm using latest WinAVR (from year 2010 lol). Tried atmel gnu toolchain but it gave me errors when compiling. Any ideas why it gets so large?

Please try a recent version of avr-gcc (better optimization)!

[madires]

Quick update on the m-firmware:
- Bug: The test button won't exit the IR detector when the IR receiver module is removed too early (endless loop).
  This is already fixed for the next version.
- IR detector: Trendy edition will support standard RC-6.
- Trendy edition will support two profiles for self-adjustment values (load & save), e.g. for two sets of probes.

[tom666]

Tried atmel gnu toolchain but it gave me errors when compiling. Any ideas why it gets so large?

If you do upgrade the AVR-GCC (I recommend to version 4.8.1) then try this fix of the compilation error (applies to Win 8, 8.1 & 10):
https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg818096/#msg818096

Note:
Check the version of the compiler with command "avr-gcc --version".

[eas]

Quick update on the m-firmware:
- Trendy edition will support two profiles for self-adjustment values (load & save), e.g. for two sets of probes.

Thanks for implementing this!  I'll have to give it a try soon.

[bitseeker]

- Trendy edition will support two profiles for self-adjustment values (load & save), e.g. for two sets of probes.

That's excellent, madires. I haven't looked if there's room hardware- or software-wise, but it would be neat to have a toggle/slide switch connected to a pin on the 328 that would tell it which profile to use. 

[madires]

Quick update on the m-firmware:
- Trendy edition will support two profiles for self-adjustment values (load & save), e.g. for two sets of probes.

Thanks for implementing this!  I'll have to give it a try soon.

I think, v1.21m is going to be a "happy new year" release 

[timelessbeing]

A number of us have built that one recently and been quite happy with it...

Is there pre-compiled firmware for my device?

Is it "mega328_st7565_kit" in the trunk directory?

It would be nice to use until I get familiar with compiling and all the make options.

[madires]

Is there pre-compiled firmware for my device?

Is it "mega328_st7565_kit" in the trunk directory?

Yup!