Author Topic: $20 LCR ESR Transistor checker project  (Read 3430842 times)

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Offline robca

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Re: $20 LCR ESR Transistor checker project
« Reply #4450 on: February 03, 2018, 07:07:24 pm »
Hi Guy's

I just purchased 2 of the AY-AT testers (1 kit, 1 assembled) and am going to install some better components.

  680ohm  0.1%
470kohm  0.1%
LM4040 2.5v ref
MCP1702 5v reg

Out of curiosity, where did you find the 680 Ohm and 470 Ohm 0.1% resistors? I can't find the exact values in 0.1% (digikey, mouser). 1% are easy to find in every value, but 0.1% are much harder
 

Offline phil from seattle

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Re: $20 LCR ESR Transistor checker project
« Reply #4451 on: February 03, 2018, 07:34:37 pm »
Hi Guy's

I just purchased 2 of the AY-AT testers (1 kit, 1 assembled) and am going to install some better components.

  680ohm  0.1%
470kohm  0.1%
LM4040 2.5v ref
MCP1702 5v reg

Out of curiosity, where did you find the 680 Ohm and 470 Ohm 0.1% resistors? I can't find the exact values in 0.1% (digikey, mouser). 1% are easy to find in every value, but 0.1% are much harder

Hmmm, just did a search on mouser found 470, 470K and 680 .1% in both smd and th. The TH ones are pricey though.
« Last Edit: February 03, 2018, 07:36:18 pm by phil from seattle »
 

Offline rddube

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Re: $20 LCR ESR Transistor checker project
« Reply #4452 on: February 03, 2018, 09:28:57 pm »
Sorry, I don't provide compiled firmware because there are too many different hardware versions. The links for the latest firmware versions:
- k-firmware: https://github.com/svn2github/transistortester/tree/master/Software/trunk
- m-firmware: https://github.com/svn2github/transistortester/tree/master/Software/Markus

Hello Madires,

I bought 2 new testers by by Electronics Studio photo attached. It is based on the ST7565 controller. I was able to compile and install the k version (1.13) by using the makefile in the mega328_MK-328 directory of trunk and all worked well.

I want to install the 1.31M version on one of the testers but I have been unable to compile a version that works. I used the ST7565R configuration of the config_328.h file, everything compiles OK but the version doesn't work. Does the M version support this controller?
 

Offline mebel

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Re: $20 LCR ESR Transistor checker project
« Reply #4453 on: February 03, 2018, 09:47:47 pm »
If the parameters in the config.h are as below then the microcontroller will use voltage regulator (  MCP1702-5002) or reference voltage (TL431)?




#define UREF_VCC         5001


//#define HW_REF25


#define UREF_25           2495



#define UREF_OFFSET      0
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #4454 on: February 03, 2018, 10:13:06 pm »
I bought 2 new testers by by Electronics Studio photo attached. It is based on the ST7565 controller. I was able to compile and install the k version (1.13) by using the makefile in the mega328_MK-328 directory of trunk and all worked well.

I want to install the 1.31M version on one of the testers but I have been unable to compile a version that works. I used the ST7565R configuration of the config_328.h file, everything compiles OK but the version doesn't work. Does the M version support this controller?

The m-firmware supports the ST7565. Presumably you need to adjust the pin assignment for the display.
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #4455 on: February 03, 2018, 10:17:46 pm »
If the parameters in the config.h are as below then the microcontroller will use voltage regulator (  MCP1702-5002) or reference voltage (TL431)?

#define UREF_VCC         5001
//#define HW_REF25
#define UREF_25           2495

#define UREF_OFFSET      0

This configuration disables the optional 2.5V external voltage reference and sets Vcc to 5001mV.
 
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Offline rddube

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Re: $20 LCR ESR Transistor checker project
« Reply #4456 on: February 03, 2018, 11:19:03 pm »
I bought 2 new testers by by Electronics Studio photo attached. It is based on the ST7565 controller. I was able to compile and install the k version (1.13) by using the makefile in the mega328_MK-328 directory of trunk and all worked well.

I want to install the 1.31M version on one of the testers but I have been unable to compile a version that works. I used the ST7565R configuration of the config_328.h file, everything compiles OK but the version doesn't work. Does the M version support this controller?

The m-firmware supports the ST7565. Presumably you need to adjust the pin assignment for the display.

Thank you Madires for your response. How does the pin assignment compare to the K version...can I deduce the pin assignment from the K version source files?
« Last Edit: February 03, 2018, 11:22:24 pm by rddube »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #4457 on: February 04, 2018, 09:26:40 am »
Before checking the display let's look for basic stuff. Does the tester turn on and stays turned on for a while (LED lit)?
 

Offline rddube

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Re: $20 LCR ESR Transistor checker project
« Reply #4458 on: February 04, 2018, 10:04:48 am »
It does turn on, but I see nothing on the screen. It stays on for approx. 45 seconds before turning off, or if I hit the Test button again.
« Last Edit: February 04, 2018, 02:03:10 pm by rddube »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #4459 on: February 04, 2018, 02:59:23 pm »
So the power control seems to work. I've checked the k-firmware's config.h for the ST7565's pin assignment and it uses the same defaults like the m-firmware. Could you please try another default value for the contrast (the MK-328's Makefile sets 55 as default)?
 

Offline robca

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Re: $20 LCR ESR Transistor checker project
« Reply #4460 on: February 04, 2018, 05:16:58 pm »
Hi Guy's

I just purchased 2 of the AY-AT testers (1 kit, 1 assembled) and am going to install some better components.

  680ohm  0.1%
470kohm  0.1%
LM4040 2.5v ref
MCP1702 5v reg

Out of curiosity, where did you find the 680 Ohm and 470 Ohm 0.1% resistors? I can't find the exact values in 0.1% (digikey, mouser). 1% are easy to find in every value, but 0.1% are much harder

Hmmm, just did a search on mouser found 470, 470K and 680 .1% in both smd and th. The TH ones are pricey though.
Do you have a link? The ones I found can only be bought in huge reels, not just one... and I'm asking about TH, not SMD, since I plan to solder them on the opposite side and use them as hook points to program the Atmega in-circuit
 

Offline GBowes

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Re: $20 LCR ESR Transistor checker project
« Reply #4461 on: February 04, 2018, 05:32:39 pm »
Not sure if this link will work.
https://www.mouser.com/Passive-Components/Resistors/_/N-5g9nZ1yzvvqx?P=1z0z819Z1z0vpm5Z1z0x74aZ1yzekil

If not, go to Mouser.com and enter the mouser part numbers in the search bar.

Mouser part numbers
279-H4680RBYA
71-RN55C-B-470K/R

Graham
 
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Offline rddube

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Re: $20 LCR ESR Transistor checker project
« Reply #4462 on: February 04, 2018, 06:36:26 pm »
So the power control seems to work. I've checked the k-firmware's config.h for the ST7565's pin assignment and it uses the same defaults like the m-firmware. Could you please try another default value for the contrast (the MK-328's Makefile sets 55 as default)?

Ok, set the contrast at 55 but still don't see anything on the screen?
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #4463 on: February 04, 2018, 08:58:29 pm »
It must be something else but I don't got any idea at the moment. Are you sure that you've enabled the ST7565 configuration?
« Last Edit: February 04, 2018, 09:04:14 pm by madires »
 

Offline rddube

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Re: $20 LCR ESR Transistor checker project
« Reply #4464 on: February 04, 2018, 09:07:27 pm »
It must be something else but I don't got any idea at the moment. Are you sure that you've enabled the ST7565 configuration?
Presume you mean this one, or maybe I have the wrong one as I don't have a rotary encoder on my tester?

*
 *  ST7565R, SPI interface (bit-bang)
 *  - settings for Electronic Assembly EA DOGM/DOGL128-6
 *  - uses LCD_CS to support rotary encoder in parallel at PD2/3
 */
#define LCD_ST7565R
#define LCD_GRAPHIC                     /* monochrome graphic display */
#define LCD_SPI                         /* SPI interface */
#define LCD_PORT         PORTD          /* port data register */
#define LCD_DDR          DDRD           /* port data direction register */
#define LCD_RESET        PD4            /* port pin used for /RES */
#define LCD_A0           PD3            /* port pin used for A0 */
#define LCD_SCL          PD2            /* port pin used for SCL */
#define LCD_SI           PD1            /* port pin used for SI (LCD's data input) */
#define LCD_CS           PD5            /* port pin used for /CS1 (optional) */
#define LCD_DOTS_X       128            /* number of horizontal dots */
#define LCD_DOTS_Y       64             /* number of vertical dots */
#define LCD_START_Y      0              /* start line (0-63) */
#define LCD_CONTRAST     55             /* default contrast (0-63) */
#define FONT_8X8_VF                     /* 8x8 font, vertically aligned & flipped */
#define SYMBOLS_24X24_VFP               /* 24x24 symbols, vertically aligned & flipped */
#define SPI_BITBANG                     /* bit-bang SPI */
#define SPI_PORT         LCD_PORT       /* SPI port data register */
#define SPI_DDR          LCD_DDR        /* SPI port data direction register */
#define SPI_SCK          LCD_SCL        /* port pin used for SCK */
#define SPI_MOSI         LCD_SI         /* port pin used for MOSI */
« Last Edit: February 04, 2018, 09:10:05 pm by rddube »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #4465 on: February 04, 2018, 09:40:38 pm »
The ATmega328's default pin assignment for the ST7565 is:

Code: [Select]
#define LCD_RESET        PD0            /* port pin used for /RES (optional) */
#define LCD_CS           PD5            /* port pin used for /CS1 (optional) */
#define LCD_A0           PD1            /* port pin used for A0 */
#define LCD_SCL          PD2            /* port pin used for SCL */
#define LCD_SI           PD3            /* port pin used for SI (LCD's data input) */
 

Offline rddube

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Re: $20 LCR ESR Transistor checker project
« Reply #4466 on: February 04, 2018, 10:26:09 pm »
The ATmega328's default pin assignment for the ST7565 is:

Code: [Select]
#define LCD_RESET        PD0            /* port pin used for /RES (optional) */
#define LCD_CS           PD5            /* port pin used for /CS1 (optional) */
#define LCD_A0           PD1            /* port pin used for A0 */
#define LCD_SCL          PD2            /* port pin used for SCL */
#define LCD_SI           PD3            /* port pin used for SI (LCD's data input) */

That worked Madires! Cool! I had to bring down the contrast back to 11 however otherwise I was getting a black box.  Will give it a test drive and report back.

Thank you for all your help, you're amazing!
 

Offline dave356

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Re: $20 LCR ESR Transistor checker project
« Reply #4467 on: February 05, 2018, 06:58:23 am »
Is this all the stuff I need to start programming the chip???
 

Offline timelessbeing

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Re: $20 LCR ESR Transistor checker project
« Reply #4468 on: February 05, 2018, 09:31:56 am »
looks about right
 

Offline oldswamm

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Re: $20 LCR ESR Transistor checker project
« Reply #4469 on: February 05, 2018, 12:29:46 pm »
I only discovered these little wonders a couple months ago.  I now own 2, an LCR-T6, all SMT, and an ay-at, through hole, and have ordered parts for upgrades to the second.
I want to sincerely thank Markus and Karl-Heinz, and all the others who helped develop and refine this.  Wish I'd had it 50yrs ago, or 40, or....

I would like to discuss an improved version, using a shield for an Arduino mega2560.  If this is already being done, or even seriously discussed, please point me to it.  And if I seem presumptuous jumping in here like this, I apologize.  It's the way I am, (I'd like to order prototype boards right after the holidays).  If this isn't already being done, and you don't hate all my ideas, it obviously should be opened in a new topic.

I'm thinking about numerous 'improvements' over the 328.  Some of my ideas may be based on misconceptions, I'll admit.  I'll try and list them (ideas, not misconceptions). 

If any user doesn't want a feature, just don't populate it.

More than 2 resistor values?  If the board were designed for 4 different resistor values, different users could populate 2, 3, or 4.  If we used 1k8, 3k6, 900k, and 1m8 at 18v, we would be able to put 5mA, 10mA, 15mA, 5uA, 10uA, and 15mA into 0 ohms.  Probably would be better to choose wider spacing such as 15mA, 3mA, 100uA, and 5uA?

Higher voltage.  I'm leaning toward 18v, mostly because that's the recommended max for the CD4066B.  If there's a better part choice, I haven't found one I like (cheap too).  I would put all 3 of one value resistor to one IC, connected to one rail, which should give the best resistance match.  2 ICs in parallel would halve the resistance, and with careful selection would reduce the mismatch.  The 4066 has a 10mA max, so would probably want to parallel the ones to the low value resistor, and the ones to 18v and ground, at least.  I expect the ones shown in red on my sketch are superfluous.

I would put pads for resistors in parallel with the lower value .1% resistors, and in series with the high value .1% resistors (have to cut a trace), so we can 'trim' them.  If you can get access to a 5-1/2 digit meter, you can measure the .1% resistors, then calculate the trim values needed (I have friends with access, I hope).  Same trick for the voltage dividers for the op amps and reference voltage.  Measure the regulator voltages while you have access to that nice meter.  It would be neat if we could push it to 4-1/2 digit accuracy.

I would make provision for a 14bit 200sps ADCs (MAX11101EUB+, OK?), or an optional cheaper 12bit.  All 3 sample and holds would be triggered simultaneously, and 3 separate serial data streams would then download simultaneously. 

I didn't find a 3p relay that I liked for shorting the inputs, so ordered some A5W-K dpdt, and will use 2 of them, which is what I would probably use for this shield.  Fairly small, and cheap.

I would include a frequency counter pre-scaler, and possibly an optional HF pre-pre-scaler (I haven't investigated, but I'll bet we can buy a 'module' for very little).  BNC(s). 

A separate zener tester.

How about a crystal oven?  2 resistors epoxied to the sides of the crystal, down against the pcb, and a thermistor epoxied to the can.  It would use 1 or 2 processor outputs connected to the resistors, and the thermistor to an adc channel.  We don't need to raise it's temperature very much, so needn't use much energy.  A little packing foam above and below would help insulate it. 

Obviously the tester would have to remain on for some time when ovens are used.  I would probably use a 5Ahr Li-Po cell, and include a USB charger jack to recharge a cell phone or tablet, thereby gaining almost unlimited on time as a bonus, so wouldn't care.  Hey, this thing would probably be in my carry-on anyway, right?

A 2 or 3 range, auto ranging volt meter.  I don't remember how to do auto ranging, and would have to research. Banana jacks.

A protected input to connect to a current shunt, 50uV?

A simple buffered waveform generator.  Once the hardware is in place, people will write increasingly complex waveforms....

The whole power supply should be on the shield, including 5v for the processor. 

Any suggestions for a voltage regulator that beats .1% significantly?  Would temperature controlled oven help there?  I even considered using another 4066 and/or transistors to switch in load resistors in an effort maintain a more constant load (as if testing loads were constant....).  Actually, if it would help, we could switch in resistors with the unused switches in the 4066s, (0 to 50mA in 2.5mA steps?).  Would have to be based on a calculation, but combined with a load resistor at the regulator, we could keep the load to within a few %.  Just thinking out load here.  The regulator seams to me to be the weak point, and I'm not sure how to improve it to the degree needed, at least not affordably.

I haven't counted, and might be pushing the pin count on the mega2560, but can always use a little logic to control the 4066s, which would save 10 or more pins.

Large color displays.  My eyes are at that age, or beyond.  :-)

I should mention that I don't want to be the one to make the software changes.  Old, cranky, and has hated programing for 40yrs+.  If we could agree on a design, I would have (bare) boards made, and would send some to someone willing to modify the software, at my own expense.

Thanks for listening,
Bob

P.S. If someone wants to help with this PM me.
I'll design the hardware, if someone wants to work on the software.
In spite of what Madires says, I think it would be reasonable to try and improve this device.  Now, not someday.
« Last Edit: February 05, 2018, 05:31:23 pm by oldswamm »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #4470 on: February 05, 2018, 01:54:29 pm »
There's already an Arduino shield made by pighixxx (http://forum.arduino.cc/index.php?topic=164112.0). He also ported the m-firmware to a sketch but the files aren't online at the moment (http://www.pighixxx.com). You aren't the first one suggesting a tester with higher test voltages and more probe resistors. One of the main benefits of the current design is its simplicity. Adding the external switching and ADCs increases the complexity of hardware and firmware. This might be an idea for the future, possibly with a totally different MCU, but not now. Our next step is to move to the ATmega644/1284 for more flash, RAM and IO pins. If you're interested in a frequency counter you'll find a simple hardware option with input buffer, prescaler and crystal oscillators in Karl-Heinz' documentation. It's supported by both firmwares (k & m). Or do you fancy a touch screen? No problem! 8)
 

Offline indman

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Re: $20 LCR ESR Transistor checker project
« Reply #4471 on: February 05, 2018, 02:01:41 pm »
Hi,Madires!
There is a question on setup of a m-firmware on ST7735.How to shift or reduce the image on this clone?
Here its settings in config_328.h
* ST7735, SPI interface (bit-bang, 4 wire)
//#if 0
#define LCD_ST7735
#define LCD_COLOR /* color graphic display */
#define LCD_SPI /* SPI interface */
#define LCD_PORT PORTD /* port data register */
#define LCD_DDR DDRD /* port data direction register */
#define LCD_RES PD3 /* port pin used for /RESX (optional) */
//#define LCD_CS PD5 /* port pin used for /CSX (optional) */
#define LCD_DC PD2 /* port pin used for D/CX */
#define LCD_SCL PD0 /* port pin used for SCL */
#define LCD_SDA PD1 /* port pin used for SDA */
#define LCD_DOTS_X 128 /* number of horizontal dots */
#define LCD_DOTS_Y 160 /* number of vertical dots */
#define LCD_FLIP_X /* enable horizontal flip */
//#define LCD_FLIP_Y /* enable vertical flip */
#define LCD_ROTATE /* switch X and Y (rotate by 90°) */
#define LCD_LATE_ON /* turn on LCD after clearing it */
#define FONT_8X16_CYRILLIC_HF /* 8x16 cyrillic font, horizontally aligned & flipped */
#define SYMBOLS_30X32_HF /* 30x32 symbols, horizontally aligned & flipped */
#define SPI_BITBANG /* bit-bang SPI */
#define SPI_PORT LCD_PORT /* SPI port data register */
#define SPI_DDR LCD_DDR /* SPI port data direction register */
#define SPI_SCK LCD_SCL /* port pin used for SCK */
#define SPI_MOSI LCD_SDA /* port pin used for MOSI */
//#endif

Whether the LCD_OFFSET_X and LCD_START_Y commands work?
 

Offline rddube

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Re: $20 LCR ESR Transistor checker project
« Reply #4472 on: February 05, 2018, 02:58:58 pm »
If you shift to the right, you won't be able to see the symbols on the right.

Looks as if the casing  opening is too narrow. Did you try it without the top cover to see if you have full image?
 

Offline oldswamm

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Re: $20 LCR ESR Transistor checker project
« Reply #4473 on: February 05, 2018, 03:01:45 pm »
Yes I've read Karl-Heinz' pdfs, and a lot of this forum topic.  I've studied all the schematics I could find.

I don't see the advantage of the ATmega644/1284 over the 2560.  If the ATmega2560 isn't enough, what processor would you suggest?

I couldn't get at the schematics for pighixxx's shield.  Was he using high voltage and hi res ADCs?  If not, I don't see the advantage.

I know I'm not the first to suggest SOME of these things.  Am I the first who wants to build it NOW?  How far in the future do you think it needs to be put off?  I don't have that many more years on this earth, so what gets postponed, pretty much is canceled as far as I'm concerned.

The firmware changes for high voltage and external ADCs shouldn't be that hard, or porting it to an arduino sketch, I just don't have the temperament for SW.  I tend to smash keyboards and other offensive parts of the computer when I do.  If none of the software folks think the improvements are worthwhile, I probably won't bother building it.

And no, it will no longer be a $20 tester.  It will cost 3 to 6 times that.  Your tester is designed to be inexpensive, and it's great for the price.  I just think the same theory of operation could be applied to a slightly more accurate, more versatile device, and am willing to accept that it will cost more.

If you really think it's a terrible idea that can't possibly be built for years to come, I'll delete my posts and go away....

If you think one of more of my ideas is wrong, please be specific.  I honestly don't see why it can't be built at this time, or for that mater on an Arduino mega2560.  I could wish it was a little faster , but it has 4 to 8 times the memory of the 328, and 3 or 4 times the ports.
Bob
 

Offline indman

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Re: $20 LCR ESR Transistor checker project
« Reply #4474 on: February 05, 2018, 03:26:20 pm »
If you shift to the right, you won't be able to see the symbols on the right.

Looks as if the casing  opening is too narrow. Did you try it without the top cover to see if you have full image?
It is correct, but I have a task how to place the image without having spoiled appearance of a tester. It is possible to cut wider hole, never late to make it  :) It is possible to reduce resolution instead of 128x160 to make 124x156
« Last Edit: February 05, 2018, 03:37:24 pm by indman »
 


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