Author Topic: $20 LCR ESR Transistor checker project  (Read 3427084 times)

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Offline Feliciano

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Re: $20 LCR ESR Transistor checker project
« Reply #7225 on: October 17, 2021, 12:06:30 am »
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.
Yes, I was thinking on tweaking only the English font, since this would be a visual aid (for older eyes) more than anything else. That would be an addon font, shall you determine that would be the best approach. I could help creating/revising that font map.

And as I said, other option would it be a traditional approach of drawing color backgrounds and foregrounds. But as you know C much better than me, I leave it to your kind consideration when you take the time to study this case.

Other thought for improving readability on 160x128 displays would it be to have a tad bigger font -with the same 32B/tile- like 12x16. What do you think?
« Last Edit: October 17, 2021, 12:29:56 am by Feliciano »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #7226 on: October 17, 2021, 10:51:17 am »
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? :)

Adding a buzzer is easy. But doing a proper continuity check in software isn't.
 

Offline indman

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Re: $20 LCR ESR Transistor checker project
« Reply #7227 on: October 17, 2021, 11:05:43 am »
But doing a proper continuity check in software isn't.
You can use a simple -3 level option that evaluates the ADC on the input:
1.Below 0.1V - continuous signal
2.Range 0.1V-0.7V p-n junction(single short signal)
3.Above 0.7V - no signal
« Last Edit: October 17, 2021, 11:11:14 am by indman »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #7228 on: October 17, 2021, 11:57:01 am »
Yes, I was thinking on tweaking only the English font, since this would be a visual aid (for older eyes) more than anything else. That would be an addon font, shall you determine that would be the best approach. I could help creating/revising that font map.

And as I said, other option would it be a traditional approach of drawing color backgrounds and foregrounds. But as you know C much better than me, I leave it to your kind consideration when you take the time to study this case.

Other thought for improving readability on 160x128 displays would it be to have a tad bigger font -with the same 32B/tile- like 12x16. What do you think?

Adding reversed characters to the font (doesn't matter if in the same font file or if it's an additional one) would add another layer of complexity to everything related. Using slightly larger characters for probe numbers would make the layout framework more complex. And we also have to deal with page organized displays. Simply reversing foreground and background colors requires additional lines at one or two sides of each character, as fonts include a fixed character spacing scheme. Again, many transistortesters have page organized displays. Unfortunately there's no easy way without increasing the firmware size significantly and maybe rendering a lot of testers obsolete. For an easy to read display I'd recommend a large ILI9341/2 based LCD (up to 3.2") and using the 16x26 font.
« Last Edit: October 17, 2021, 12:14:28 pm by madires »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #7229 on: October 17, 2021, 12:05:51 pm »
You can use a simple -3 level option that evaluates the ADC on the input:
1.Below 0.1V - continuous signal
2.Range 0.1V-0.7V p-n junction(single short signal)
3.Above 0.7V - no signal

I see. I'll put it on the to-do list.
 
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Offline indman

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Re: $20 LCR ESR Transistor checker project
« Reply #7230 on: October 17, 2021, 12:12:55 pm »
I see. I'll put it on the to-do list.
I'm sorry we're not letting you get bored and relaxed with our new ideas. :D
 
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Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #7231 on: October 17, 2021, 12:20:45 pm »
Poor me! ;D
 
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Offline Feliciano

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Re: $20 LCR ESR Transistor checker project
« Reply #7232 on: October 17, 2021, 05:06:33 pm »
Once more, thanks for all your support.

As reversing some colors looks too complicated, I think I would create a bold or semibold 10x16, or try to use a 12x16 font for the ST7335 (some reason for not being an option on the current config644.h?).

BTW: I looked into the 12x16_hf and spotted 3 errors (flipped first diode, wrong Ä, and the Ü=ü) (iirc, somebody already reported the diode error). If that font is viable, I'll look how to fix those characters.
« Last Edit: October 18, 2021, 12:43:47 am by Feliciano »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #7233 on: October 17, 2021, 06:54:31 pm »
The 12x16_hf (also 2x16_iso8859-2_hf) isn't used yet because it allows only 13 characters per line on a 160 pixel wide display. If you want to use it with an ST7735 you need to add '#include "font_12x16_hf.h"' to the driver and set FONT_12X16_HF in the display configuration.
 

Offline bffargo

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Re: $20 LCR ESR Transistor checker project
« Reply #7234 on: October 18, 2021, 01:23:47 am »
The san-serif font just posted above is great. It's crisp and clear. The ones with thin edges to then accommodate serifs are much harder to read. Standard 8-bit block fonts from the 80's are much easier.
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #7235 on: October 18, 2021, 11:06:01 am »
Since we're talking about fonts, there's an option in the m-firmware to display the whole font. Enable SW_FONT_TEST in config.h and you'll get a menu item "Font".
 

Offline Feliciano

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Re: $20 LCR ESR Transistor checker project
« Reply #7236 on: October 18, 2021, 04:40:46 pm »
The fonts bitmaps I've been attaching recently have been rendered on my computer from the actual font file (simulating a display under a ~5x zoom), to ponder how it would look, and spot for little bugs and/or things to improve before compile/flashing it.

If you guys already have the font loaded to your device, you can use the optional Font menu on the m-firmware, or it can be shown at the end of the show data on the k-firmware.
« Last Edit: October 18, 2021, 05:24:24 pm by Feliciano »
 

Offline robca

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Re: $20 LCR ESR Transistor checker project
« Reply #7237 on: October 18, 2021, 05:28:08 pm »
You can use a simple -3 level option that evaluates the ADC on the input:
1.Below 0.1V - continuous signal
2.Range 0.1V-0.7V p-n junction(single short signal)
3.Above 0.7V - no signal

I see. I'll put it on the to-do list.
Not sure if it's possible with the existing circuit, but this is an interesting implementation of a continuity tester using an ATtiny85 http://www.technoblogy.com/show?1YON
 

Offline indman

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Re: $20 LCR ESR Transistor checker project
« Reply #7238 on: October 18, 2021, 05:42:50 pm »
Not sure if it's possible with the existing circuit, but this is an interesting implementation of a continuity tester using an ATtiny85 http://www.technoblogy.com/show?1YON
There are enough devices of this kind on the internet, simple and more complicated, on Arduino, ATiny, Pic controllers. But it will be very goot if autors adapt this function to the tester. ;)
 

Offline Dumidan

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Re: $20 LCR ESR Transistor checker project
« Reply #7239 on: October 19, 2021, 11:51:17 am »
If we keep talking about additional functions for the tester, it might be interesting to add a logic probe function with selection, from the menu, for TTL / CMOS level.

In the case of CMOS it would be good to be able to select the supply voltage in the range 3.3V - 15V.

The measuring input can be for external voltage.

It would not require hardware changes, only software.
« Last Edit: October 19, 2021, 11:54:12 am by Dumidan »
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #7240 on: October 19, 2021, 02:09:35 pm »
If your tester has the 10:1 voltage divider for the Zener check but no boost converter we could use that input. The ratio of the voltage divider isn't ideal for 18 V or so, but it should work. Some testers have that 10:1 voltage divider for measuring an external voltage up to 50 V. Another idea is a temporary voltage divider at the probes, but I don't like that (some silly mistake could kill the ATmega easily). So I'd prefer an unused ADC pin with an optimal voltage divider and some simple and robust input protection.
 

Offline Feliciano

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Re: $20 LCR ESR Transistor checker project
« Reply #7241 on: October 20, 2021, 12:23:26 pm »
Quick question: the special B-like character on the font file, is supposed to be the greek beta (β) or the german esstsett (ß)?
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #7242 on: October 20, 2021, 12:53:33 pm »
The one just after the upper case umlauts is the ß (Eszett, or sharp s).
 

Offline Dumidan

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Re: $20 LCR ESR Transistor checker project
« Reply #7243 on: October 20, 2021, 01:17:35 pm »
I have three testers (clones). In order of purchase: LCR-T4, M328 KIT COLOR (AY-AT) and LCR TC-1 (with ATmega324).

For the M328 KIT COLOR (AY-AT) I was thinking of adding an 80k resistor (1: 5 ratio) for the additional logic tester input, using the same PC3 port and 20k ground resistor, as for the voltmeter function.

From SRV05-4 only 3 protection circuits are used; the fourth can be used to protect PC3.

For me, hardware modification is not a problem, but software modification is. I am a beginner in programming. madires can you please help me, tell me what exactly I should add / modify in the software?
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #7244 on: October 20, 2021, 02:01:15 pm »
To just measure the voltage:
- Enable HW_ZENER, ZENER_DIVIDER_CUSTOM and ZENER_UNSWITCHED.
- Set ZENER_R1 and ZENER_R2
 

Offline Dumidan

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Re: $20 LCR ESR Transistor checker project
« Reply #7245 on: October 20, 2021, 06:54:18 pm »
Thanks for the reply madires, but I think I did not express myself intelligibly enough.

My intention is to introduce a new "logic tester" function, with "TTL" and "Vcc - CMOS" submenu options, where Vcc can be selected in the 3.3V - 15V range.
"L" or "H" or "Indefinite or HiZ" or "Pulse" should be displayed on the screen, as the voltage value on the ADDITIONAL pin "Test logic input" falls within the logic levels:

For TTL (Vcc = 5V)
- L => 0V to 0.8V
- H => 2V to 5V
- Undefined / HiZ => 0.8V up to 2V

For CMOS (Vcc = 3.3V up to 15V)
- L => 0V up to 1/3*Vcc
- H => 2/3*Vcc to Vcc
- Undefined / HiZ => 1/3*Vcc to 2/3*Vcc

Can I make the necessary changes / additions, considering that I am a beginner in programming?
If so, I would need some guidance on how to intervene in the script.
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #7246 on: October 20, 2021, 07:30:37 pm »
I think it would better to wait until I have the time to add the logic probe function, because it would take more time to explain all the details.
 
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Offline bffargo

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Re: $20 LCR ESR Transistor checker project
« Reply #7247 on: October 22, 2021, 08:30:45 pm »
I picked up a LCR-T4: The 128x64 LCD arrived broken on the top left overhang. The top half of the display is dead but bottom works perfectly.

I was curious if there was any way to get either alternate firmware to work on this making it think it was a 128x32 display forcing everything into the lower half (or having it treat it like a 1602 in a way?) as it would be fully usable then.  Now: Diodes, Transistors = cut off, caps and inductors mostly okay.

Screens cost more than a new T4; no sense to try to replace the screen. I was originally going to mod it to 16MHz.
 

Offline madires

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Re: $20 LCR ESR Transistor checker project
« Reply #7248 on: October 22, 2021, 10:36:15 pm »
Should be an ST7565 based display which is easy to get. To just use the working half of the display you would have to modify the display driver in the firmware.
 

Offline Dumidan

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Re: $20 LCR ESR Transistor checker project
« Reply #7249 on: October 23, 2021, 06:41:05 am »
@bffargo:

In my experience, an LCD display that has been broken in one corner will be completely damaged in a relatively short time, on the order of months.
You better replace it with another graphic display that you have at hand - anyway I understood that you will have to change its software, if you want to change the quartz with a 16MHz one.
 


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