Design a New Precision LCR Tweezers with Much Lower Cost(Video Attached)

[Shannon]

Yeah I think you are right, its across FET gate, then 1k series resistor into an IO pin. So maybe one of those is slightly turning on. The Auto mode works very well most of the time, and here it detects as 10k exactly, so I should be in that mode instead.

For RDC:
The ST42 voltage across goes from 0.570V to 0.508V during its test.
The Fluke only delivers 80mV when testing the 10k. It may not be possible to achieve this low voltage.

One other Auto example, inductor of 4.9uH 100mR resistance:
- in 100/120Hz it will read as a resistor
- in 1kHz, 10kHz it reads as an inductor
Maybe intended, OK for me, as I should be in 10kHz mode when measuring inductance.

Thanks for your test.
Fluke use 80mV to measure 10kohm means the current is 8uA.

We think the best way is to add auto range mode to the DCR function, this feature is in our TODO list now.
Even though the DCR measurement is not the advantage of ST42, we will make it better as well.

For the 100Hz 4.9uH inductor, the impedance is very small, ST42 cannot distinguish the inductor from the DCR resistor.
Z = 2*pi*f*L = 2*3.14*100*4.9uH = ~3mohm, which is very small, and mush smaller than the DCR 100mohm.

As you mentioned, the auto mode is suited for most of the applications.

[Shannon]

Hi there,

New firmware has been released. Here is the update:
v1.4.2   2022/6/27   fix >100mH level inductor measurement stuck issue
        fix self-calibration may stuck
        added left/right button function to exit/enter menu
        added alarm for unaccepted button

welcome to upgrade to the latest version, the joystick control is much more fluent and meets user habits.
And two small probability bugs have also been fixed.

[tautech]

Hi there,

New firmware has been released. Here is the update:
v1.4.2   2022/6/27   fix >100mH level inductor measurement stuck issue
        fix self-calibration may stuck
        added left/right button function to exit/enter menu
        added alarm for unaccepted button

welcome to upgrade to the latest version, the joystick control is much more fluent and meets user habits.
And two small probability bugs have also been fixed.

Went looking for it since you didn't provide a link or file to download...... and it was easy to find. 
https://shannontweezers.top/docs/upgrading-firmware/

[bicycleguy]

Hi there,

New firmware has been released. Here is the update:
v1.4.2   2022/6/27   fix >100mH level inductor measurement stuck issue
        fix self-calibration may stuck
        added left/right button function to exit/enter menu
        added alarm for unaccepted button

welcome to upgrade to the latest version, the joystick control is much more fluent and meets user habits.
And two small probability bugs have also been fixed.

Went looking for it since you didn't provide a link or file to download...... and it was easy to find. 
https://shannontweezers.top/docs/upgrading-firmware/

The link above has link 'firmware-uploader.zip' which opens v1.3.9, not the latest.  Edit: This works a little differently than what I've used before in that the updater is some software that sits on your machine and doesn't need updated.  It loads the firmware from some server and installs it into the device.  So when the latest firmware is wanted you use the same updater, no need to download it again.  So this was the second update for me.

[dibro]

I've just updated my tweezers and it installed 1.4.2
But I used the updated I had already installed previously.
And I use the linux version of the updated.

[TheDefpom]

I just received my Shannon Tweezer for review, as it took a while to get shipping to actually carry it it is on firmware 1.3.8, so I am trying to update to the latest firmware but as I use a Mac I am having some difficulties trying to get it done.

Has anyone else here done a firmware update using a Mac that can give me some pointers ?

I tried a couple of things, opened terminal and dragged the file in to get the path and tried to run, this gives this error:

Code: [Select]

[5311] Error loading Python lib '/var/folders/p7/_xtlbn497yl4wfx8j1jv7ysh0000gn/T/_MEIXEUaLl/Python': dlopen: dlopen(/var/folders/p7/_xtlbn497yl4wfx8j1jv7ysh0000gn/T/_MEIXEUaLl/Python, 10): no suitable image found.  Did find:
/var/folders/p7/_xtlbn497yl4wfx8j1jv7ysh0000gn/T/_MEIXEUaLl/Python: cannot load 'Python' (load command 0x80000034 is unknown)
/private/var/folders/p7/_xtlbn497yl4wfx8j1jv7ysh0000gn/T/_MEIXEUaLl/Python: cannot load 'Python' (load command 0x80000034 is unknown)

So I tried specifying python and then dragging the file in to get the path and running that, and that gives this error:

Code: [Select]

  File "/Users/scott/Documents/Shannon Tweezer/fw-update-5.26/fw_update-mac", line 1
SyntaxError: Non-ASCII character '\xcf' in file /Users/scott/Documents/Shannon Tweezer/fw-update-5.26/fw_update-mac on line 1, but no encoding declared; see http://python.org/dev/peps/pep-0263/ for details

I don't have much experience with using python or terminal to do these kinds of tasks, so I am hoping that it is something simple I am missing, at least once I figure that out I can include instructions in the review video.

[bicycleguy]

@TheDefpom
I forgot to mention to Shannon that I had the same problem with a mac running Catalina macOS 10.15.7.  I ended up using a windoz 11 pc.

I did investigate and found something that indicated the problem may be related to the App Shannon made is using a Python library for a newer mac that called a function _preadv that is only available on newer macs.  _preadv is implemented in the older libraries but uses the mac version which is newly available.  The article stated that the problem is in the Python library installation and that some maintainers had fixed it and some hadn't.  Apparently the library distribution Shannon uses hasn't.

Symbol not found: _preadv
  Referenced from: /var/folders//.../Python (which was built for Mac OS X 12.0)
  Expected in: /usr/lib/libSystem.B.dylib

So there is nothing you can do about it other than waiting for Shannon to fix it or use a different machine.

edit.  The ironic thing is the function isn't even used, but the library expects it !

[TheDefpom]

I am on an older mac, I use a 2012 Mac Pro running on MacOS 10.12 (I cant upgrade due to other software limitations, such as not wanting to pay for Adobe Premiere and Photoshop until the end of time itself as I already own them).

In case it helps here is my Python info:

Code: [Select]

Python 2.7.10 (default, Feb  7 2017, 00:08:15)
[GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.34)] on darwin


[KungFuJosh]

I am on an older mac, I use a 2012 Mac Pro running on MacOS 10.12 (I cant upgrade due to other software limitations, such as not wanting to pay for Adobe Premiere and Photoshop until the end of time itself as I already own them).

In case it helps here is my Python info:

Code: [Select]

Python 2.7.10 (default, Feb  7 2017, 00:08:15)
[GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.34)] on darwin


I did that for a while too. I eventually gave in and subscribed, but I hate the subscription model, even if I do like some of the changes to their suite. I did pretty well though, I had CS6 since 2012, or 2013 and finally upgraded this year.

Can't you dual boot into linux or windows on your mac to run the firmware update?

Thanks,
Josh

[TheDefpom]

Review video is now public:

[TheDefpom]

A suggestion Shannon from my usage experience so far.

In the menu can you please change the highlighting to show the current setting, and use the arrow to indicate the cursor, that way it is possible to look through the menu and be able to see what the current settings are.

[ebastler]

Hi Shannon, can the tweezers be ordered on AliExpress at the moment -- and can they be shipped to Germany at all?

The link given on your shannontweezers.top home page, https://www.aliexpress.com/item/1005004239869204.html, takes me to a message "The page you requested cannot be found -- this item cannot be shipped to Germany".  The link to your AliExpress store, https://www.aliexpress.com/store/1102064026, seems to work; but the store does not offer any products.

Thank you for a quick clarification. Are you out of stock, or are you excluding orders from Germany at this time?

[Shannon]

Hi Shannon, can the tweezers be ordered on AliExpress at the moment -- and can they be shipped to Germany at all?

Thank you for a quick clarification. Are you out of stock, or are you excluding orders from Germany at this time?

we can open these two link without the last comma.

You can try to search "shannon tweezers st42" on aliexpress platform

[Shannon]

I am on an older mac, I use a 2012 Mac Pro running on MacOS 10.12 (I cant upgrade due to other software limitations, such as not wanting to pay for Adobe Premiere and Photoshop until the end of time itself as I already own them).

In case it helps here is my Python info:

Code: [Select]

Python 2.7.10 (default, Feb  7 2017, 00:08:15)
[GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.34)] on darwin


Thanks Defpom,

we have tried to contact you by email, if you have time, you can use the e-mail attached new version have a try.
We didnot have the dedicated Mac version, so we setup a virtual environment to verify the firmware update program.
Hope it works

[Shannon]

Review video is now public

Many thanks for your video, it's the first Shannon Tweezers ST42 review video, it's awesome 

There is a problem when you did the onboard diode bridge detection.
The root cause is ST42 need to detect the direction of the diodes, so the excitation current is always changing in a period,
If the diode is in parallel with a large capacitor, ST42 can not charge the capacitors to a relatively higher voltage in a short time,
and then ST42 found the voltage between two tips is quite low, so ST42 thinks it's shorted

We will try to use a larger current and longer detection period to make it better for this case.

[ebastler]

we can open these two link without the last comma.
You can try to search "shannon tweezers st42" on aliexpress platform

Thank you for the quick reply, Shannon. I have fixed the links in my post above, where the forum software had included the comma in the link -- sorry about these; don't know how often I have fallen into that trap...

But the problem seems to lie elsewhere. Both links give me the results described above; I do not see the actual product offering. And when searching for "shannon tweezers st42", AliExpress shows me all kinds of (passive) tweezers, but not your product.

It looks to me like you have limited the list of countries where you want to sell/ship the product, when setting things up on the AliExpress site. Hence AliExpress does not show it to me in a search or when looking at your shop. And when I try to open the product page directly, it tells me "does not ship to Germany".

Could you please check whether Germany is included, and add the country in case it is not? Thank you!

[dibro]

@ebastler
If I try your URL's from the Netherlands I see the offers, both URL's work.
No idea why it doesn't work for you.

[picburner]

I confirm what ebastler said. If I set Germany as country, the shop disappears, but with the country setting Italy the shop is perfectly visible and I can buy.

[ebastler]

Thank you both for checking, dibro and picburner! Let's hope it is just a simple country setting on AliExpress which Shannon can fix. I'll check back here tomorrow, and will also try the AliExpress offer again.

[TheDefpom]

This morning I decided to make the review a 2 part as I didn't really go into the accuracy aspect in the first review, so I recorded some more video this morning showing it testing my standard capacitors and I also used it on my Fluke 5450A resistance calibrator.

I will publish the 2nd part next week.

[Shannon]

Thank you both for checking, dibro and picburner! Let's hope it is just a simple country setting on AliExpress which Shannon can fix. I'll check back here tomorrow, and will also try the AliExpress offer again.

I find out the reason, why you cannot access the ST42 on Aliexpress platform.
There is a new policy in Germany, called EPR(extended-producer-responsibility)
Here is the link:
https://www.lizenzero.de/en/blog/extended-producer-responsibility-epr-in-germany-everything-you-need-to-know-now-to-continue-selling-on-amazon-co./
https://www.epr-compliance.com/
After July 1 2022, all the sellers should register the compliance, if he want to sell goods to Germany,
otherwise, the platform will block the goods' information and sales prohibited 

We are now consulting on how to complete the registration, we will reply the result in few days.

[ebastler]

There is a new policy in Germany, called EPR(extended-producer-responsibility)
[...]
After July 1 2022, all the sellers should register the compliance, if he want to sell goods to Germany,
otherwise, the platform will block the goods' information and sales prohibited 

Ouch... Germany, as well as many other European countries, have had regulations in place for years which require the manufacturers of electronic devices, as well as the manufacturerers/distributors of packaging, to join suitable recycling schemes and company registers. But it seems a bit over the top to start enforcing the packaging requirements (but not the electronics requirements?) for international companies which ship directly to end users.

This is Germany's implementation of an EU-wide directive. While the individual countries can choose different ways to translate these directives into national law, it is likely that other European countries will take similar approaches. Seems that France has similar requirements in place already?

So it will make sense for you to find a way to comply. There are probably service providers which can act as your agent and provide registration and waste disposal services, for Germany and whichever other countries implement similar requirements in the future. I guess you would have to include their fees in a higher shipping cost to Germany.

Ahh, but we are saving the world -- from incorrectly disposed packaging for LCR tweezers in this case... 
Sorry about the complications!

[grizewald]

I just got my order in from Sweden.
I've had my eye on these tweezers since I first saw this thread and I'm really looking forward to receiving mine!

[battlecoder]

Well I just found out about these tweezers today and I've been reading through the thread.
There's definitely a few things that can be improved, from what I'm reading, but seems to work quite well for most tasks.
Fantastic job Shannon.

[TheDefpom]

Part 2 of the review: