$20 LCR ESR Transistor checker project

[Yuriy_K]

Hi majortom,

I do not publish my sources due to their strong difference from the last version of the Karl-Heinz sources. In the sources, the font and formulas for calculating inductance and capacitance have been changed, and many color control commands have been added. All the changes are too long to list. Everything that can be published, you can try suitable for MG328A.

[Obelix2007]

Hi majortom,

the open source idea is interpreted one-sidedly by some people!

Greeting Horst

[indman]

the open source idea is interpreted one-sidedly by some people!

Address these reproaches to Chinese friends who churn out these devices in thousands of pieces and sell them without paying any attention to open source idea!

[Maniaxx]

Anything wrong with this self-adjustment setup? It always shows 'Error!' after adjustment (still shows value screen though).
I just have 2 clamps so i've put some shorter solid core cable in TP2. Maybe TP2 cable needs to be same length/type as well?
Cable 1+3 are stranded wire.

Short cables (2x solid core cable) for self-adjustment do work.

[madires]

Please post the values displayed during the self-adjustment. My guess would be that the probe resistance is too high.

[indman]

Short cables (2x solid core cable) for self-adjustment do work.

Such short cables are desirable. Long and thin wires with high internal resistance as well as wires that introduce significant additional capacitance and inductance must not be used with this device!

[Maniaxx]

Long and thin wires with high internal resistance as well as wires that introduce significant additional capacitance and inductance must not be used with this device!

So, thick wires are better? I will try 1.5mm² and somewhat shorter then.

Please post the values displayed during the self-adjustment.

I've attached the self-adjustment procedure with the setup shown above.

Is there any documentation for the self-adjustment values beside the source code annotations in 'adjust.c'?

[madires]

At step A6 the capacitance between probes #2 and #3 is 113pF for the first run. The limits are noted in the README:

Code: [Select]

Limits:
- probe resistance   < 1.50 Ohms for two probes in series
- probe capacitance  < 100 pF
- IO pin's internal resistance in low mode (RiL)   < 25 Ohms
- IO pin's internal resistance in high mode (RiH)  < 29 Ohms

Have you measured a film cap (100nF - 3.3µF) three times before running the self-adjustment?

[Maniaxx]

Looks like its the PSU (H+H SN1000). I suspect the multi plug interface (its somewhat loose). The device itself shouldn't be that bad. It's a heavy trafo (not a small switching one). With battery everything's fine.

1) When i measure 680Ohm (0.1%) i get (quite stable) 677.5Ohm no matter how its adjusted or with/without cables. 470k (0.1%) shows 469.5k that should be ok i guess.
Can i shift the RL value? There is 'RH_OFFSET' in config.h but no 'RL_OFFSET'.

2) I have a 470uF 63V cap. When testing in normal mode it shows 471uF 0.38Ohm. In 'C-Monitor' it shows 453uF with a slightly higher ESR. Do they have different testing methods?

[horo]

Hi,

If you want to create your own firmware version, choosing the right compiler version can noticeably reduce the code size.
I recently did a comparison of different avr-gcc versions. I took all the versions available for Linux (Debian stable) and compiled a 1.50m (with an identical setup for my AY-AT with 20 MHz xtal).
These are the results:

Code: [Select]

avr-gcc v. 12.1.0
Program:   35988 bytes (109.8% Full)
Data:        269 bytes (13.1% Full)
EEPROM:       22 bytes (2.1% Full)
avr-gcc v. 11.1.0:
Program:   35252 bytes (107.6% Full)
Data:        269 bytes (13.1% Full)
EEPROM:       22 bytes (2.1% Full)
avr-gcc v. 10.1.0
Program:   35196 bytes (107.4% Full)
Data:        251 bytes (12.3% Full)
EEPROM:       22 bytes (2.1% Full)
avr-gcc v. 9.2.0
Program:   35190 bytes (107.4% Full)
Data:        251 bytes (12.3% Full)
EEPROM:       22 bytes (2.1% Full)
avr-gcc v. 9.1.0
Program:   35190 bytes (107.4% Full)
Data:        251 bytes (12.3% Full)
EEPROM:       22 bytes (2.1% Full)
avr-gcc v. 8.3.0
Program:   32546 bytes (99.3% Full)
Data:        251 bytes (12.3% Full)
EEPROM:       22 bytes (2.1% Full)
avr-gcc v. 8.2.0
Program:   32536 bytes (99.3% Full)
Data:        251 bytes (12.3% Full)
EEPROM:       22 bytes (2.1% Full)
avr-gcc v. 8.1.0
Program:   32536 bytes (99.3% Full)
Data:        251 bytes (12.3% Full)
EEPROM:       22 bytes (2.1% Full)
avr-gcc v. 7.3.0 (Arduino-Version)
Program:   32612 bytes (99.5% Full)
Data:        251 bytes (12.3% Full)
EEPROM:       22 bytes (2.1% Full)
avr-gcc v. 5.4.0 (Debian-Stable-Version)
Program:   32742 bytes (99.9% Full)
Data:        251 bytes (12.3% Full)
EEPROM:       22 bytes (2.1% Full)

Based on these results, I set 8.3.0 (the last of the major version 8 ) as default.
For later review, I enabled "link-time optimisation" with the compiler switch "-flto", which reduced the code size even further:

Code: [Select]

avr-gcc v. 8.3.0 (my default)
Program:   31770 bytes (97.0% Full)
Data:        244 bytes (11.9% Full)
EEPROM:       22 bytes (2.1% Full)

avr-gcc v. 7.3.0 (Arduino-Version)
Program:   31810 bytes (97.1% Full)
Data:        244 bytes (11.9% Full)
EEPROM:       22 bytes (2.1% Full)

avr-gcc v. 5.4.0 (Debian-Stable-Version)
Program:   32096 bytes (97.9% Full)
Data:        244 bytes (11.9% Full)
EEPROM:       22 bytes (2.1% Full)


Martin

[madires]

1) When i measure 680Ohm (0.1%) i get (quite stable) 677.5Ohm no matter how its adjusted or with/without cables. 470k (0.1%) shows 469.5k that should be ok i guess.
Can i shift the RL value? There is 'RH_OFFSET' in config.h but no 'RL_OFFSET'.

You could try to adjust R_LOW.

2) I have a 470uF 63V cap. When testing in normal mode it shows 471uF 0.38Ohm. In 'C-Monitor' it shows 453uF with a slightly higher ESR. Do they have different testing methods?

No, both use the same measurement functions. Different probes?

[Maniaxx]

Same probes. ZIF socket shows same behavior. Tried different power supplies and different caps. Testing resistors is ok.

'Default Test' vs. 'C-Monitor':
1063uF <> 1016uF
463uF <> 444uF
103uF <> 100uF
222nF <> 222nF

The first two measurements of 'C-Monitor' are higher then the following. I have 'hold' values enabled. Maybe the test cycles are too fast?
Not sure if relevant, i have MCP1702 installed with Vref and 2.2k still in place (but disabled in config.h).

Can someone confirm or falsify this behavior?

[indman]

Same probes. ZIF socket shows same behavior. Tried different power supplies and different caps.

Madires, I have the same effect on my clones, but I didn't pay much attention to it.
I made 2 short videos so you can better understand what I'm talking about. I measure the same capacitance 1000uFx10V on ZIF pins 1-3. In the RLC monitor mode, the tester first shows the same capacitance value as in normal testing, but then the result decreases jump. I don't know what is the reason for this behaviour?
https://drive.google.com/file/d/1DSnLMSiL0VmlU29ebRCczFxiez6BJ08C/view?usp=sharing
https://drive.google.com/file/d/1lwazwLodpxfv2d3wuUisQfvdH8jAHm17/view?usp=sharing

[madires]

Does that happen only for electrolytic caps?

[ledtester]

If you want to create your own firmware version, choosing the right compiler version can noticeably reduce the code size.
...

This is rather incredible! Do you have any idea of what's going on?

Could you post the assembly output from the 8.3 and 12.1 compilers? I would be interested in comparing the two.

See this link for generating an assembly listing interleaved with source:

https://stackoverflow.com/a/1289907

[indman]

Does that happen only for electrolytic caps?

Yes, only on electrolytic capacitors, I didn't notice it on other families.

I recently did a comparison of different avr-gcc versions. I took all the versions available for Linux (Debian stable) and compiled a 1.50m (with an identical setup for my AY-AT with 20 MHz xtal).

Can you show your settings file for the config.h clone - I'm interested to compare the size of the firmware that will be with my compiler on Windows?

[madires]

Could be dielectric absorption as the polarity stays the same for all measurements in the C monitor (and C measurement in the LCR monitor).

[indman]

madires,hm... but then we should see exactly the same effect on a k-firmware clone if we measure the same capacitance first on pins 1-2 and then on pins 1-3, on which the monitor mode is automatically turned on? But I do not observe such an effect, or am I wrong? This effect does not bother me much, since I know that electrolytic capacitors can have a large deviation from the nominal capacity. But it was just interesting to understand why.

[prashk20]

Hello!

I pulled in the 1.50m firmware and ran it on my Arduino Uno. Most of the functions work well except a specific range of resistors. Schematics is mostly based on AY-AT clone.

Before I go on about the issue, I want to thank everyone who is building this amazing instrument. Thank you!

Now the problem. I know Arduino Uno and Component Tester on a breadboard is not the best accuracy, but I get error of under 1% on most resistors, except a range where it gives 50% error.
Correct Readings of Resistors within 1%: 220, 330, 470, 1k, 2.2k, 220k, 470k, 1M.

Incorrect Readings of Resistors: 10 as 5, 100 as 50, 4.7k as 14k, 10k as 4.2k, 22k as 9.9k, 47k as 21.5k, 100k as 44k.
 

I am using 1% resistors as of now and not required 0.1%. I'm not sure if this is the issue because 220 is read correctly but not 100 and 2.2k is correct. 200K is correct but 100K is read as 44K.
This issue is not specific to a set of probe pins. The issue is only with a range of resistors, while another range is read correctly, I wonder what the mistake here might be.

The self adjustment doesn't seem to work. After shorting the probes, it calculates Ri+-, etc., and on next click gives an error.
And the LEDs are not working. (Update: got LEDs working)
Any ideas?



Attached are pictures.
Makefile and config modifications and output is here: https://github.com/pk17r/Transistortester-Warehouse/tree/prash/ComponentTester-1.50m_Arduino_Uno

[madires]

madires,hm... but then we should see exactly the same effect on a k-firmware clone if we measure the same capacitance first on pins 1-2 and then on pins 1-3, on which the monitor mode is automatically turned on? But I do not observe such an effect, or am I wrong? This effect does not bother me much, since I know that electrolytic capacitors can have a large deviation from the nominal capacity. But it was just interesting to understand why.

That asks for some further investigation.

Update:
The issue can happen when the electrolytic cap creates a negative voltage in respect to the measurement polarity. Karl-Heinz has solved this in the k-firmware by using a voltage divider to shift the reference point to about 140 mV which allows to also measure a small negative voltage. Both firmwares measure the cap's unloaded voltage after discharging the cap to get the zero offset.

[madires]

The self adjustment doesn't seem to work. After shorting the probes, it calculates Ri+-, etc., and on next click gives an error.

Please post the values displayed during the self-adjustment.

[Yuriy_K]

Any ideas?

Hello!

  For your circuit to work correctly, you need to modify ARDUINO_UNO. Replace the 1000 pF capacitor and cut the trace to input 5 of the op amp, marked with an X.

[horo]

Could you post the assembly output from the 8.3 and 12.1 compilers? I would be interested in comparing the two.

See this link for generating an assembly listing interleaved with source:

https://stackoverflow.com/a/1289907

I get different output formats for 8.3.0 and 12.1.0, the newer version contains the source code while the old version lacks it.
I attached the compiler output of both versions as well as the disasm (which looks similar to the already produced listing lss).
I had to tar both tar.gz archives because the forum doesn't like tar.gz or tgz.

7.3.0:

Code: [Select]

0000338a <MeasureESR>:
    338a: a4 e0        ldi r26, 0x04 ; 4
    338c: b0 e0        ldi r27, 0x00 ; 0
    338e: eb ec        ldi r30, 0xCB ; 203
    3390: f9 e1        ldi r31, 0x19 ; 25
    3392: 0c 94 d6 3e jmp 0x7dac ; 0x7dac <__prologue_saves__>
    3396: 9c 83        std Y+4, r25 ; 0x04
    3398: 8b 83        std Y+3, r24 ; 0x03
    339a: 89 2b        or r24, r25
    339c: 51 f4        brne .+20      ; 0x33b2 <MeasureESR+0x28>
    339e: 2f ef        ldi r18, 0xFF ; 255
    33a0: 3f ef        ldi r19, 0xFF ; 255
    33a2: 3c 83        std Y+4, r19 ; 0x04
    33a4: 2b 83        std Y+3, r18 ; 0x03
    33a6: 8b 81        ldd r24, Y+3 ; 0x03
    33a8: 9c 81        ldd r25, Y+4 ; 0x04
    33aa: 24 96        adiw r28, 0x04 ; 4
    33ac: e2 e1        ldi r30, 0x12 ; 18
    33ae: 0c 94 f2 3e jmp 0x7de4 ; 0x7de4 <__epilogue_restores__>
    33b2: eb 81        ldd r30, Y+3 ; 0x03
    33b4: fc 81        ldd r31, Y+4 ; 0x04
    33b6: 63 81        ldd r22, Z+3 ; 0x03
    33b8: 74 81        ldd r23, Z+4 ; 0x04
    33ba: 85 81        ldd r24, Z+5 ; 0x05
    33bc: 96 81        ldd r25, Z+6 ; 0x06
    33be: a7 ef        ldi r26, 0xF7 ; 247
    33c0: ea 2e        mov r14, r26
    33c2: 0a e0        ldi r16, 0x0A ; 10
    33c4: 10 e0        ldi r17, 0x00 ; 0
    33c6: 20 e0        ldi r18, 0x00 ; 0
    33c8: 30 e0        ldi r19, 0x00 ; 0
    33ca: 42 81        ldd r20, Z+2 ; 0x02
    33cc: 0e 94 a5 11 call 0x234a ; 0x234a <CmpValue>
    33d0: 87 fd        sbrc r24, 7
    33d2: e5 cf        rjmp .-54      ; 0x339e <MeasureESR+0x14>
    33d4: 0e 94 f4 13 call 0x27e8 ; 0x27e8 <DischargeProbes>
    33d8: 80 91 91 01 lds r24, 0x0191 ; 0x800191 <Check>
    33dc: 81 30        cpi r24, 0x01 ; 1
    33de: f9 f2        breq .-66      ; 0x339e <MeasureESR+0x14>
    33e0: eb 81        ldd r30, Y+3 ; 0x03
    33e2: fc 81        ldd r31, Y+4 ; 0x04
    33e4: 11 81        ldd r17, Z+1 ; 0x01
    33e6: 00 81        ld r16, Z
    33e8: 17 b8        out 0x07, r1 ; 7
    33ea: 18 b8        out 0x08, r1 ; 8
    33ec: 14 b8        out 0x04, r1 ; 4
    33ee: 15 b8        out 0x05, r1 ; 5
    33f0: 40 e0        ldi r20, 0x00 ; 0
    33f2: 61 2f        mov r22, r17
    33f4: 80 2f        mov r24, r16
    33f6: 0e 94 b4 10 call 0x2168 ; 0x2168 <UpdateProbes>


12.1.0:

Code: [Select]

00004614 <MeasureESR>:
 *  - ESR in 0.01 Ohm
 *  - UINT16_MAX on any problem
 */

uint16_t MeasureESR(Capacitor_Type *Cap)
{
    4614: a7 e0        ldi r26, 0x07 ; 7
    4616: b0 e0        ldi r27, 0x00 ; 0
    4618: e0 e1        ldi r30, 0x10 ; 16
    461a: f3 e2        ldi r31, 0x23 ; 35
    461c: 0c 94 a4 44 jmp 0x8948 ; 0x8948 <__prologue_saves__>

00004620 <.L1^B33>:
    4620: 8e 83        std Y+6, r24 ; 0x06
    4622: 9f 83        std Y+7, r25 ; 0x07

00004624 <.LVL1075>:
  uint32_t          Sum_1;         /* sum #1 */
  uint32_t          Sum_2;         /* sum #2 */
  uint32_t          Value;

  /* check for a capacitor >= 10nF */
  if ((Cap == NULL) ||
    4624: 2e 81        ldd r18, Y+6 ; 0x06
    4626: 3f 81        ldd r19, Y+7 ; 0x07
    4628: 23 2b        or r18, r19
    462a: 51 f4        brne .+20      ; 0x4640 <.L605>

0000462c <.L607>:
      (CmpValue(Cap->Value, Cap->Scale, 10, -9) < 0)) return ESR;
    462c: 6f ef        ldi r22, 0xFF ; 255
    462e: 7f ef        ldi r23, 0xFF ; 255
    4630: 7a 83        std Y+2, r23 ; 0x02
    4632: 69 83        std Y+1, r22 ; 0x01

00004634 <.L604>:
  Cfg.Ref = ADC_REF_BANDGAP;       /* we've used the bandgap reference */

  DischargeProbes();               /* discharge DUT */

  return ESR;
}
    4634: 89 81        ldd r24, Y+1 ; 0x01
    4636: 9a 81        ldd r25, Y+2 ; 0x02
    4638: 27 96        adiw r28, 0x07 ; 7
    463a: e2 e1        ldi r30, 0x12 ; 18
    463c: 0c 94 c0 44 jmp 0x8980 ; 0x8980 <__epilogue_restores__>

P.S.:
This linker option gives even more space, from 32562 bytes down to 32044 bytes (avr-gcc-8.3.0):

Code: [Select]

LDFLAGS += -Wl,--relax

[majortom]

I built the aur package for avr-gcc 8.5, and played around this morning to compare to avr-gcc 13.2.0.
My differences weren't nearly as impressive as horo, but using CFLAGS += -flto definitely helped to
squeeze a couple more features in there that wouldn't have otherwise fit.
GCC 13.2 below was prior to adding some features that normally wouldn't have fit, like IR Detector.

Was earlier this AM, and after a long day of work I might have missed a step here in my description.
edit: and saw similar with the linker --relax switch as well.
 
config.h
https://pastebin.com/Zag8JYRk
config_328.h
https://pastebin.com/jsVF55sL

Code: [Select]


avr-gcc (GCC) 8.5.0
AVR Memory Usage
----------------
Device: atmega328

Program:   32920 bytes (100.5% Full)
(.text + .data + .bootloader)

Data:        265 bytes (12.9% Full)
(.data + .bss + .noinit)

EEPROM:      884 bytes (86.3% Full)
(.eeprom)

avr-gcc (GCC) 8.5.0
CFLAGS += -flto
AVR Memory Usage
----------------
Device: atmega328

Program:   32342 bytes (98.7% Full)
(.text + .data + .bootloader)

Data:        263 bytes (12.8% Full)
(.data + .bss + .noinit)

EEPROM:      884 bytes (86.3% Full)
(.eeprom)


avr-gcc (GCC) 13.2.0
AVR Memory Usage
----------------
Device: atmega328

Program:   28926 bytes (88.3% Full)
(.text + .data + .bootloader)

Data:        261 bytes (12.7% Full)
(.data + .bss + .noinit)

EEPROM:      756 bytes (73.8% Full)
(.eeprom)

avr-gcc (GCC) 13.2.0
CFLAGS += -flto
AVR Memory Usage
----------------
Device: atmega328

Program:   28044 bytes (85.6% Full)
(.text + .data + .bootloader)

Data:        260 bytes (12.7% Full)
(.data + .bss + .noinit)

EEPROM:      756 bytes (73.8% Full)
(.eeprom)


[prashk20]

The self adjustment doesn't seem to work. After shorting the probes, it calculates Ri+-, etc., and on next click gives an error.

Please post the values displayed during the self-adjustment.

The values are:
Ri- 20.0Ohm
Ri+ 22.0Ohm
C0 43pF
R0 0.20Ohm
Vref 1008mV
Vcc 5001mV
AComp -45mV

Next page on click is Error.

I went through your note on Self-Adjustment (Many many thanks for the superb documentation  , I first used a 2.2uF cap several times before doing this.)

I am using Arduino Uno as of now for prototyping, but will use a Atmega1284 chip or a Teensy 4.0 microcontroller (if suitable) for my finished tester.