Design a New Precision LCR Tweezers with Much Lower Cost 【Shannon Tweezers ST42】

[Shannon]

Part 2 of the review:

Thanks a lot for the accuracy review video, the performance is very nice.
Except two issue,
1. 1nF test result is around 1%
2. Rdc measurement is not suitable for the large resistance.

And the feeling is like this 
https://youtu.be/6s2UJBFDCoA

To be honest, we cannot repeat the 1nF test accuracy issue in this stage, it’s not easy to get a 0.1% accuracy cap.
But we are serious about the second Rdc measurement issue,
We aimed at ~0.1% accuracy for the AC excitation mode for L/C/R,
So the Rdc accuracy is ignored by general test,
But we think there must be room for optimization, give us some time.

The 1nF cap accuracy measurement issue, could you help us use another accurate LCR to verify the standard capacitor value? We want to confirm this issue, it’s little strange
We have no idea about the cause

[Shannon]

Part 2 of the review:

Thanks a lot for the accuracy review video, the performance is very nice.
Except two issue,
1. 1nF test result is around 1%
2. Rdc measurement is not suitable for the large resistance.

New firmware version is released, which fixed the second RDC issue , here is the link: https://shannontweezers.top/docs/upgrading-firmware/

Thanks to TheDefPom’s accuracy review video, we fixed the resistor measurement noise bug in v1.4.2.

Please let us know if you encountered any issue with Shannon Tweezers, we definitely will improve it in short time.

The AUTO mode is also suitable discrete resistor measurement. In fact, AC excitation signal with DFT analysis leads to better noise and accuracy performance since the DC offset in circuit is eliminated compared to DC signal measurement.

The DC resistance measurement is now enabled with both 50Hz and 60Hz notch filter, so the noise introduced via long lead and large resistance can be reduced greatly.

[Kean]

Received my Shannon Tweezers today.  First impression is very good.  Firmware updated.   

[TheDefpom]

Where are the latest firmware versions ?

I tried download from the site but I just seem to keep getting the same version for some reason as I did a month ago, with a modified date of 26/5/22, called "fw-update-5.26", the site lists up  to 1.4.4 but I don't think the file I am getting is it, as the file names, sizes and dates are identical to what I downloaded some time ago, at the time of 1.4.2, which I am not even sure was right at the time either as these dates are from May, before those updates.

Is it just some random quirk or is my browser not actually getting the latest version downloaded?

[Kean]

Where are the latest firmware versions ?

I tried download from the site but I just seem to keep getting the same version for some reason as I did a month ago, with a modified date of 26/5/22, called "fw-update-5.26", the site lists up  to 1.4.4 but I don't think the file I am getting is it, as the file names, sizes and dates are identical to what I downloaded some time ago, at the time of 1.4.2, which I am not even sure was right at the time either as these dates are from May, before those updates.

Is it just some random quirk or is my browser not actually getting the latest version downloaded?

I believe the updater downloads the latest version at run time.  Which is not ideal, but I suspect is an intentional decision for IP protection.
I was thinking of running Wireshark while updating to see what it does...

[picburner]

In fact, by default the updater updates to the latest firmware version, but as you can see from the help you can also specify a different version (but I haven't tried if this really works).

[ebastler]

A quick note for others in Germany who might be interested in the ST42 tweezers:

Shannon has now signed up with a service provider to comply with the packaging (recycling) requirements, and the tweezers can be shipped to Germany. The direct product link, https://www.aliexpress.com/item/1005004239869204.html, as well as the Shannon Store link, https://www.aliexpress.com/store/1102064026, both work for me now. Just ordered my tweezers!

[Shannon]

Where are the latest firmware versions ?
I am not even sure was right at the time either as these dates are from May, before those updates.
Is it just some random quirk or is my browser not actually getting the latest version downloaded?

I believe the updater downloads the latest version at run time.  Which is not ideal, but I suspect is an intentional decision for IP protection.
I was thinking of running Wireshark while updating to see what it does...

As kean mentioned, the commandline tool by default downloads the latest firmware from server and push it to device. Please make sure there is internet connectivity before running the tool.
And we can check the firmware version by system->service->version menu

[Grandchuck]

Shannon Tweezers were ordered on July 17 and they arrived here today in SW Florida.  Good packaging and the case is sturdy.  They work as expected.  I will be testing ranges, functions and accuracy ... so far everything looks spot on!

[grizewald]

My tweezers arrived at my local post agent in Sweden earlier today. Here's a slightly longer version of the review I left on Aliexpress:

Shannon's tweezers are the perfect example of what happens when someone looks critically at the products currently on the market, identifies what is wrong with each of them and then sets out to make something better than anything that already exists.

These tweezers are everything that they should be. They are small and light, they fit in your hand perfectly and are truly ergonomic. They offer a large measurement range and are very accurate on all ranges. The display is logical, comprehensive and easy to read. The joystick control also follows a logical approach and I was right at home selecting test frequency, excitation voltage and measurement mode within minutes.

Mechanically, the design and execution is a triumph! Due to the fact that there is virtually no side to side movement when opening and closing the tweezer's jaws, you really can pick up a 0402 sized capacitor and place it down accurately every time. I don't know of any other tweezers which have solved this basic and critical aspect, which is why I have never bought a pair of measuring tweezers before. I'd seen how poor the mechanical aspect was on all the others and knew that I would end up throwing them out of the window when I had the third component jump out of the jaws and onto the floor!

Firmware updates are easy and regular as Shannon continues to improve the firmware based on feedback from customers. Even better, the updater runs on Windows, Mac and Linux, just like it should! The tweezers arrived with the latest version 1.4.4 firmware already installed.

Congratulations Shannon, this is a great product at a fair price and is every bit as good as I expected!

[Grandchuck]

Accuracy checks are all good.  Usability is also good.  However, I am seeing some curvature at the probe tips.  Photo attached.

[thm_w]

I did buy some replacement tips from Shannon, as I had started to ruined the original ones, but it was nothing like that. The material looks like gold plated steel.

Maybe you got a bad batch that wasn't properly hardened.

[Shannon]

Accuracy checks are all good.  Usability is also good.  However, I am seeing some curvature at the probe tips.  Photo attached.

We did produce two batches of tweezer tips,
but the difference between them is that the thickness of the first batch of tweezers remains at 0.2~0.3mm, and the thickness of the second batch is about 0.1mm.

The tips of the first batch of tweezers will be much stronger, but are not as good as a good tweezer when picking up small parts.
There are two reasons, the first is that the thickness is indeed thicker than a good quality tweezers, and the second is that the gold plating is done by electroplating, and the surface of the gold layer is very smooth.

So we changed the tip of the tweezers to be more pointed. You should be the latter batch. Both batches are made of the same material, using high hardness stainless steel and then gold plated.

Before production, we also studied the difference between good tweezer tips and bad tweezer tips, better tweezers, their tweezer arms tend to fit well, not just the tweezer tips touching together, so you will find When over-clamping the ST42's tweezer arms, the tweezer tips will be slightly separated to protect the tweezer tips and prevent the components from falling off.
And you know there is no tweezer tip to complete the action of tilting things. Similarly, if you fall from a table with a height of 1m to a hard ground, the tweezer tip will also be knocked crooked.

As thm_w said, we were more worried about the wear of the gold plating layer, and the surface impedance will be relatively large, even if these errors can be calibrated out, but this problem still exists, which is why we are wondering if there is a better 4-wire structure.

We are sorry about the bent tip of your ST42 tweezers.
And we are a little curious about how the tip of your tweezers is bent.
We want to understand the use case, and then try to optimize it and give users some reminders, Thanks.

[Shannon]

Congratulations Shannon, this is a great product at a fair price and is every bit as good as I expected!

Thank you very much for your support.
You have felt a lot of details that we have designed with heart. This is what really moved us.
Good things can connect everyone together. I believe that most of the time people's experience of beauty can be very close.
What we do is not a cold instrument, we want it to be elegant.
We're really trying to optimize those details that users really care about, trying to make it the best it can be.

Thanks again, without your support, we would not be able to persistently improve this matter

[Grandchuck]

Accuracy checks are all good.  Usability is also good.  However, I am seeing some curvature at the probe tips.  Photo attached.

We did produce two batches of tweezer tips,
but the difference between them is that the thickness of the first batch of tweezers remains at 0.2~0.3mm, and the thickness of the second batch is about 0.1mm.

The tips of the first batch of tweezers will be much stronger, but are not as good as a good tweezer when picking up small parts.
There are two reasons, the first is that the thickness is indeed thicker than a good quality tweezers, and the second is that the gold plating is done by electroplating, and the surface of the gold layer is very smooth.

So we changed the tip of the tweezers to be more pointed. You should be the latter batch. Both batches are made of the same material, using high hardness stainless steel and then gold plated.

Before production, we also studied the difference between good tweezer tips and bad tweezer tips, better tweezers, their tweezer arms tend to fit well, not just the tweezer tips touching together, so you will find When over-clamping the ST42's tweezer arms, the tweezer tips will be slightly separated to protect the tweezer tips and prevent the components from falling off.
And you know there is no tweezer tip to complete the action of tilting things. Similarly, if you fall from a table with a height of 1m to a hard ground, the tweezer tip will also be knocked crooked.

As thm_w said, we were more worried about the wear of the gold plating layer, and the surface impedance will be relatively large, even if these errors can be calibrated out, but this problem still exists, which is why we are wondering if there is a better 4-wire structure.

We are sorry about the bent tip of your ST42 tweezers.
And we are a little curious about how the tip of your tweezers is bent.
We want to understand the use case, and then try to optimize it and give users some reminders, Thanks.

The tips were bent making measurements on printed circuit boards.  I don't think I used excessive force?  Also, I was not trying to probe through heavy corrosion or solder masks or anything of that nature.

Otherwise, very pleased with your product.

Thanks for responding.

[sarming]

I was just talking with my spouse wether to buy the LCR Pro1 tweezers when I found this project.
Well, my Shannon tweezers arrived earlier this week It took 18 days from ordering to delivery in Austria, in excellent packaging.

I really like the physical construction. The tips work very well, maybe could be a bit more symmetric/identical and better finished (one a a tiny blemish on the side) but are what I would expect from a good pair of (regular) 15€ tweezers. This is really great!

I played around and collected some feedback/suggestions (see below) but after charging on my MacBook it froze at "charging 100%". I wanted to add to list of suggestions to change the display to "charged" and shutdown after unplugging from the charger but then realized  it was completely frozen. I tried all sorts combinations of key presses and plugging in/out, UART, looking for and reset switch and waited about 10 minutes (timeout was set to 60s) to avail. I opened it up and (seeing that the LiPo seemed well protected) shorted the power pins. After turning it back on the calibration was obviously wrong (eg. shortened tips showed -38kOhm, was unable to light the test board LED). A reset to factory cal did not change the problem, neither did uploading the firmware (v1.4.4).  When I tried self cal it froze again (at 0%). After another hard reset and leaving it turned off for some time,  everything seemed normal again, but then suddenly was out of cal again (same -38kOhm as before) when trying to calibrate it froze again - this time in the open procedure.
After another crowbar reset everything again seemed fine but then the Auto mode showed no primary parameter and the other modes where again wrong. Switching off and waiting solved this. Since then I have been able to run a full calibration process and it did not freeze again (could it be related to high battery voltage?) Now I sometimes get the -38kOhm that don’t go away with calibration (neither full procedure nor factory) but often disappear after switching off (and waiting). So maybe I have a defective unit.


At least once when frozen the unit still reacted to key presses with beeps, so even a soft reset functionality (e.g. holding center for 10s to reset) that could be implemented via a software update would have helped in this case.

Here are my other suggestions/feedback that don’t seem to be related to the specific unit I have:
- Out of range values should be indicated by < or > signs. At least show ">2.38V" instead of "2.39V" in LED mode and "VF >1.17V" instead of "VF 1.17V" in diode mode - so that one immediately sees that is the maximum possible. The same might be done for small or negative values (e.g. "<0.001pF").
- It would be nice to be able to switch it on by touching the tips together (maybe this needs a hardware revision).
- I would like diodes to be included in auto mode (at least when test-voltage is 1.0V).
- It should be called "series" and "parallel" (second one is correct in device menu but still wrong on help sheet).
- Long press short cuts would be nice but of course need thought to get right. My suggestions would be:  left -> auto mode, right -> quickset, up -> auto frequency, and maybe: down -> shutdown.

[tautech]

In my view FWIW today SMD smart tweezers need be offered with fine tips as optional and supplied with more rugged tips for the vast majority of use.
After 15 years of hobby use the original tips in my ST3 tweezers are still in good shape and they have been abused, no doubts about that.
Today now we're down to 0201 they are much too small for a generic do everything tip that must also offer a good service life.

Shannon IMO needs go back to the design bench and draw up at least 2 different size tips and maybe different styles of them too.

[Shannon]

So maybe I have a defective unit.


At least once when frozen the unit still reacted to key presses with beeps, so even a soft reset functionality (e.g. holding center for 10s to reset) that could be implemented via a software update would have helped in this case.

Here are my other suggestions/feedback that don’t seem to be related to the specific unit I have:
- Out of range values should be indicated by < or > signs. At least show ">2.38V" instead of "2.39V" in LED mode and "VF >1.17V" instead of "VF 1.17V" in diode mode - so that one immediately sees that is the maximum possible. The same might be done for small or negative values (e.g. "<0.001pF").
- It would be nice to be able to switch it on by touching the tips together (maybe this needs a hardware revision).
- I would like diodes to be included in auto mode (at least when test-voltage is 1.0V).
- It should be called "series" and "parallel" (second one is correct in device menu but still wrong on help sheet).
- Long press short cuts would be nice but of course need thought to get right. My suggestions would be:  left -> auto mode, right -> quickset, up -> auto frequency, and maybe: down -> shutdown.

Thanks a lot for your reply.
Let's try to figure out the frozen problem firstly.

Have you try to using screwdriver make the tips more stable?
You can help us observe if the 4 white insulating ring is broken, these white insulating ring protect the tips(test signal) from the ground.
if the screw breaks through the insulating ring, the test will be frozen as you mentioned.

[sarming]

Let's try to figure out the frozen problem firstly.

Have you try to using screwdriver make the tips more stable?
You can help us observe if the 4 white insulating ring is broken, these white insulating ring protect the tips(test signal) from the ground.
if the screw breaks through the insulating ring, the test will be frozen as you mentioned.

The freezing problem is hard to figure out because it is not easy to reproduce. It did not freeze again after the 3 times I mentioned above. Please note that the first time was while charging and before I performed any calibration procedure.

I have not touched the screws of the tips before. I now unscrewed them and the 4 white rings look a bit deformed but intact. I then screwed them back in tightly and measured resistances of about 20 MOhms (did not think of doing that before unscrewing).

[Grandchuck]

I continue to be impressed by the Shannon tweezers.  My latest discovery is with a 2700 uF capacitor.  The ST handles it just fine at 1 kHz.  Two other insturments only work when the test frequency is decreased.

I know that lower frequencies are better/required when testing large capacitors, but it is admirable that ST work without changing the test frequency.

[thm_w]

In my view FWIW today SMD smart tweezers need be offered with fine tips as optional and supplied with more rugged tips for the vast majority of use.
After 15 years of hobby use the original tips in my ST3 tweezers are still in good shape and they have been abused, no doubts about that.
Today now we're down to 0201 they are much too small for a generic do everything tip that must also offer a good service life.

Shannon IMO needs go back to the design bench and draw up at least 2 different size tips and maybe different styles of them too.

Its a good idea to have two tip sizes. Maybe a wider flatter end that would fit the full width of say 0603 or 0805.
The issue is how do you get it to pierce any flux or oxide layer, without a sharp point? Machining something would be tough, like the tips of pogo pins: https://www.qatech.com/images/resources/tip-selection/Bead_Bump_Dome.jpg

[tautech]

In my view FWIW today SMD smart tweezers need be offered with fine tips as optional and supplied with more rugged tips for the vast majority of use.
After 15 years of hobby use the original tips in my ST3 tweezers are still in good shape and they have been abused, no doubts about that.
Today now we're down to 0201 they are much too small for a generic do everything tip that must also offer a good service life.

Shannon IMO needs go back to the design bench and draw up at least 2 different size tips and maybe different styles of them too.

Its a good idea to have two tip sizes. Maybe a wider flatter end that would fit the full width of say 0603 or 0805.
The issue is how do you get it to pierce any flux or oxide layer, without a sharp point? Machining something would be tough, like the tips of pogo pins: https://www.qatech.com/images/resources/tip-selection/Bead_Bump_Dome.jpg

Simple, by improving the tip design and making them suitably robust.

Canadian Smart Tweezers had this situation solved more than a decade ago and if Shannon wants to compete with premium products and I believe he does then he needs lift his game.
Just looked on their website quickly and didn't spot a listing for just the tip options like I thought there was but did find listings for new tweezers with a selection of tips.
https://smarttweezers.3dcartstores.com/



Edit
Found them, even a whole range of spares for my 15+ yr old ST3:
https://smarttweezers.3dcartstores.com/Replacement-Test-Leads-Straight-PN-STAD-TS_p_21.html

[thm_w]

The tip design looks close to the Smart Tweezers though. Unless the Smart Tweezers specifically call out what steel/material they are using, then its probably not that simple to figure out.
For reference, Shannon tweezers are 0.82mm thick, tapering at 5.5mm from tip, down to about 0.35x0.35mm at the end.

[tautech]

The tip design looks close to the Smart Tweezers though. Unless the Smart Tweezers specifically call out what steel/material they are using, then its probably not that simple to figure out.

You think ?

If we look at the image from Grandchuck it's very obvious Shannons quality control or core tip design is at fault when with tips that fine used for 'in circuit' testing it's very plain they are just not fit for purpose !



To get the tweezer hinge design as good as it apparently is and overlook the tip design is quite a mistake although not everyone has a set of tweezers for the 15+ years I have and used in the wide range of use I have.
In circuit component testing is a very important part of service work so to capture a good market share they need be able to do all these tasks without batting an eyelid.

[Shannon]

The tip design looks close to the Smart Tweezers though. Unless the Smart Tweezers specifically call out what steel/material they are using, then its probably not that simple to figure out.

You think ?

To get the tweezer hinge design as good as it apparently is and overlook the tip design is quite a mistake although not everyone has a set of tweezers for the 15+ years I have and used in the wide range of use I have.
In circuit component testing is a very important part of service work so to capture a good market share they need be able to do all these tasks without batting an eyelid.

You are all right for the reasons I mentioned earlier.

At the beginning, the thickness of the tweezers tip was 0.3mm, which was similar to the width, but I felt that the strength was enough,
so I tried to adjust the thickness to be smaller. At this time, the thickness reached ~0.1mm.
You know every coin has two sides.

I believe that part of thm_w's hand is 0.3mm thick tweezers, and 0.3mm tweezers tip is fine and strong enough.
We are already arranging production orders for 0.3mm thick tweezer tips, 0.1mm tweezer tips will be phased out in the future, or as an additional option.

More than two years ago, at the beginning of designing the tweezer tip, we tried a lot of materials to balance the conductance and strongness,
and also contacted a big manufacturer specializing in tweezers to get some advice.

Various shapes and types of tweezer tips are necessary, and we will improve the design priority of this part.

Thanks for your suggestions.
Your praise or criticism will be the driving force for our optimization, so your feedback is the most important,
just like at the beginning of this project, you are responsible for the requirements, and we are responsible for the realization.