Author Topic: Design a New Precision LCR Tweezers with Much Lower Cost(Video Attached)  (Read 114521 times)

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Offline ceut

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Re: Design a New Precision LCR Tweezers with Much Lower Cost(Video Attached)
« Reply #650 on: April 11, 2024, 09:10:45 pm »
I was a little away from Eevblog because of some personal problems.

Nice work!

Thank you very much  :D

Well I went into this thread once again, this time because I was having problems updating my ST42 so it's funny that you say "hope you are the only unlucky guy who has this problem" because I'd like to introduce myself: Hi, I'm another unlucky guy, it seems :/ I'm getting exactly the same error, and I'm not really happy to hear it's a hardware problem. Is replacing the chip the only solution?

EDIT2: I would like to add that I remember updating the firmware when I was having the screen glitches (which I also reported here). And I don't remember the process giving me errors that time. Maybe this is not necessarily a hardware problem (in my unit at least) but rather that the sofware gives the same error under different conditions (including faulty hardware).

EDIT3: Ok, "solved" the issue and I'd like to keep a record here despite being a very silly mistake from my part. Apparently the intimidating error shown by the updater is the same in case of any problem communicating with the device. In my case it was either a driver issue or a cable issue, because changing the cable and usb port I got it to work.
BUT I also got the same error during one attempt in which I didn't enter into bootloader mode correctly. The COM port appeared on my computer but it wasn't in *actual* bootloader mode.

So I'd like to leave this post here as a warning for others: Even if you get the same error, it does not mean it's a hardware error. As obvious as it is now, the firmware updater will give the same error in any case in which the device is not responding back.
I'm happy to read that, as it was finally only a software/setting problem  ;)
For me, the RX pin of the chip was shorted to ground  :palm: Since I put the new one, no problem at all  :-+

For @shannon: I have checked the new diode signal: it is now super clean  :-+
I have not used it a lot since my fix, so I don't know what is new in the 1.54 version ?
@Shannon: Do you have a changelog or something like that ? With that, I can continue to suggest some ideas I could have  :)


 

Offline ceut

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Re: Design a New Precision LCR Tweezers with Much Lower Cost(Video Attached)
« Reply #651 on: April 11, 2024, 09:19:02 pm »
@Shannon how difficult do you think it would be to implement a special electrolytic capacitor testing mode? Electrolytic caps are polarized, and thus the correct way to test them is (I think) to bias the test signal to the Vpp/2 level, so that it always stays above zero instead of the standard AC signal of +/- Vpp/2.

I'm not sure what difference it will make though, but it just seems to me that applying a reverse polarity voltage to electrolytic caps, even if low and only for a half period, isn't quite right -- might be from the cap damage or the measurement precision perspective, or both. There are some LCR meters that implement this biased signal mode, e.g. East Tester ET432/433. I'm not able to find any good info on this topic, only vague suggestions that it's "better" to test the electrolytics with a positively biased signal, and it gives better precision.

It would be great to have that.
Also, as I was looking for a LCR Tweezer before Tautech told me about Shannon's one, here is the LCR-MPA function table, which I think may be added for some of them (the blue one would be great  8) ) ?
 

Offline KungFuJosh

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Re: Design a New Precision LCR Tweezers with Much Lower Cost(Video Attached)
« Reply #652 on: April 21, 2024, 12:35:36 am »
No need to wait any longer, just update your tweezers right now. >:D

Is there a new firmware release? Your website still says 2023/5.

Just upload the new firmware a momenta ago, the website information has not been update.
And there are some other modification is under processing. ;)

Hey Shannon, any update regarding the newer firmware? The OTA tool still downloads the older firmware, and the website also says 5/23.

Also, it's probably a good idea to add Shannon ST42 Tweezers to this thread title by now. 😉
"I installed a skylight in my apartment yesterday... The people who live above me are furious." - Steven Wright
 
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Offline kladit

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Re: Design a New Precision LCR Tweezers with Much Lower Cost(Video Attached)
« Reply #653 on: April 23, 2024, 10:40:11 am »
I managed the update on my linux now.

My tweezer is detected by the kernel (type dmesg to see) as:

usb 1-4: Product: USB Serial
ch341 1-4:1.0: ch341-uart converter detected

lsusb shows it as:
ID 1a86:7523 QinHeng Electronics CH340 serial converter

udev mapped it to (type dmesg to see) :
usb 1-4: ch341-uart converter now attached to ttyUSB0

Now take the shutted down tweezer, press its navigator button upwards and put in the usb-connector
of the usb-cable already conected to your computer.

Now cd to the dir where you have the unzipped  fw_update-linux programm and type :

mkdir ./tmp; export TMPDIR=./tmp; ./fw_update-linux  ttyUSB0

Now the firmware gets loaded over the internet and is flashed to the tweezer.


« Last Edit: April 27, 2024, 12:01:51 pm by kladit »
 

Offline m.abdelwanis

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Any info about ESR table or calibration ?
 


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