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

[Shannon]

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.

Thank you for your reply, I will send you a PM and we will see if there is a better way for us to gather more information.

- 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").

Agreed, it's a nice suggestion, the description of result is more accurate

- It would be nice to be able to switch it on by touching the tips together (maybe this needs a hardware revision).

We will consider this function which may need to modify the hardware version.

- I would like diodes to be included in auto mode (at least when test-voltage is 1.0V).

YES, this topic has been mentioned many times, that could be very cool, priority++

- It should be called "series" and "parallel" (second one is correct in device menu but still wrong on help sheet).

Yes, we have checked the spelling of "parallel" in the menu, and you are right

- 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.

Generally speaking, they will automatically shut down for a period of time when they are not used, and then a full charge can be used for a quite long time, and the test is almost a whole day, so shutting down is not a commonly used function, but when you encounter those case you mentioned, the buzzer can still work, but the screen is frozen. Long press to shut down or long press to restart is a very critical way. Otherwise, you need to open them, which is too complicated

[jusaca]

Can the tweezers also be used to simply measure voltages inside the circuit?
It would be really handy to just be able to measure voltages over SMD parts one-handed, but from the documentation it seems to that a simple voltage measurement is not possible?

[thm_w]

Can the tweezers also be used to simply measure voltages inside the circuit?
It would be really handy to just be able to measure voltages over SMD parts one-handed, but from the documentation it seems to that a simple voltage measurement is not possible?

I wouldn't consider using them for this purpose as its so easy to damage them once the voltage goes over ~5V or so.
You can buy banana to tweezer adapters, and use a regular DMM.

[Shannon]

Can the tweezers also be used to simply measure voltages inside the circuit?
It would be really handy to just be able to measure voltages over SMD parts one-handed, but from the documentation it seems to that a simple voltage measurement is not possible?

I wouldn't consider using them for this purpose as its so easy to damage them once the voltage goes over ~5V or so.
You can buy banana to tweezer adapters, and use a regular DMM.

As thm_w mentioned, voltage measurement by LCR meter is not as simple as you think
LCR meter is focus on precision small voltage measurement
DMM focus on high range voltage measurement
Looks like if we just add a resistor divider for LCR meter, the LCR meter could measure high voltage as well,
But the story is much more complicated, the parallel resistor divider will parallel with DUT as well, that will have impacted on the LCR test accuracy,
And if you want measure high range voltage, the resistor divider need switch gain
That is not easy

The other solution is using mechanical switch to select “voltage” or “LCR” measurement,
The problem is it’s easy for users to destroy the lcr function by high voltage measurement,
I believe every nuts has similar experience, such as using DMM current measure function to measure the voltage

[Brumby]

I bought a simple tweezer with banana leads for just this purpose.

I would strongly recommend against trying to fit in such a function.  Let the product be very good at what it was originally designed to do - and not compromise that for the sake of trying to be all things to all people.

[tautech]

I would strongly recommend against trying to fit in such a function.  Let the product be very good at what it was originally designed to do - and not compromise that for the sake of trying to be all things to all people.

Yet ST3 had a graphing function with a + 8Vp-p max rating some 15+ years ago.

Some might use it but I never have in all them years except to show the feature in a thread a few years back.



So it certainly can be done however if I need take such a measurement out comes the scope, or if just AC or DC, the DMM. Why risk frying a set of SMD tweezers ? 

[jusaca]

Ah that's a pitty, but your explanation makes sense.
The banana to tweezer adapters are new to me, they might actually be worth it. Still annyoing to have the cables flapping around and cluttering the bench, but better than nothing

[tautech]

Ah that's a pitty, but your explanation makes sense.
The banana to tweezer adapters are new to me, they might actually be worth it. Still annyoing to have the cables flapping around and cluttering the bench, but better than nothing

There's heaps of DMM tweezers like these if you go looking:

[jusaca]

These seem to be the standard ones, I found them all over the place. But the tips don't seem to be up to a task like probing an 0402 resistor, especially not when it is necessary to pierce through some conformal coating.
I was just playing with the idea to build my own with some nice pointy pogo pins and glue them to some random tweezers...

[ono]

Hi @Shannon. I am using your tweezers since Dec 21, 2022 and I find them very useful and comfortable to use, however I often have a problem to make a good contact with tips. I found that unscrewing the tips and cleaning both the main unit contacts and the tips' contacting side with isopropyl helped a lot. Still I have an impression I often need to grip and press firmly to get a reasonable readout. Is this normal?

Otherwise I like the small but very readable screen. IMHO better than larger MS8911. Also I like very gentle but audible mouse-like beeps this unit makes. I keep playing with electronics in the evenings in the quiet and I hate devices doing extra loud beeps for no good reason and yours not only allows turning the beeps off but also changing its level. Kudos!

Obviously the readouts for low resistance components are not super precise and I can obtain much more stable and precise values with dedicated milliohm or battery meters. But it is absolutely enough for checking the components on the PCBs.

Couple of suggestions/questions:
1. Can you detect open-loop OL. At the moment the unit never detects it, but rather show random high +-2-3GOhm values, I assume this is just some kind of noise being amplified. Can you detect this and show OL instead if the variance of the measurement is too high for anything that makes sense?
2. Can you make press and hold instant (without countdown) turn off? (Similar to how you turn on the device) At the moment in v1.4.4 in my unit it does nothing except beeping. I'd love to have a quick way to turn it off. Of course like you said in the previous posts the timeout should work okay and I should not worry about the battery life etc. But I just have a habit and I like turning off things myself 
3. Can you make the unit beep once when it is turned off, both manually and with timeout?

Btw. Is IdealTek ST-5 some kind of rebranded ST42? It really looks almost the same, except the UI layout being slightly different and price noticeably higher. 

[ebastler]

Btw. Is IdealTek ST-5 some kind of rebranded ST42? It really looks almost the same, except the UI layout being slightly different and price noticeably higher. 

Hmm... I had not come across the IdealTek ST5 tweezers before. But it turns out that Shannon has, well before he designed his own tweezers: https://www.eevblog.com/forum/testgear/lcr-tweezers-test-and-analysis/

So it seems that the Shannon tweezers are essentially a knock-off of the IdealTek ST5 -- at least as far as the exact form factor, tweezer construction, user interface and functionality are concerned. I would be interested in seeing a comparison of the PCB design; my suspicion is that Shannon took a lot of cues from the ST5 in this respect also. I sure hope that the firmware was independently developed and not blatantly copied.

This sours my perception of the Shannon tweezers. I still like using mine since they work well. But the whole story of "after years of research I found the right way to build these" takes on a different color. Was it really necessary to clone the mechanical design and user interface outright? 

EDIT: IdealTek actually seems to be a distributor only; their own expertise is in mechanical tweezers. The actual manufacturer appears to be SmartTweezers in the US, which explains the product name too: https://www.smarttweezers.com/st5s/.

[tautech]

Btw. Is IdealTek ST-5 some kind of rebranded ST42? It really looks almost the same, except the UI layout being slightly different and price noticeably higher. 

Hmm... I had not come across the IdealTek ST5 tweezers before. But it turns out that Shannon has, well before he designed his own tweezers: https://www.eevblog.com/forum/testgear/lcr-tweezers-test-and-analysis/

So it seems that the Shannon tweezers are essentially a knock-off of the IdealTek ST5 -- at least as far as the exact form factor, tweezer construction, user interface and functionality are concerned. I would be interested in seeing a comparison of the PCB design; my suspicion is that Shannon took a lot of cues from the ST5 in this respect also. I sure hope that the firmware was independently developed and not blatantly copied.

This sours my perception of the Shannon tweezers. I still like using mine since they work well. But the whole story of "after years of research I found the right way to build these" takes on a different color. Was it really necessary to clone the mechanical design and user interface outright? 

EDIT: IdealTek actually seems to be a distributor only; their own expertise is in mechanical tweezers. The actual manufacturer appears to be SmartTweezers in the US, which explains the product name too: https://www.smarttweezers.com/st5s/.

Yes well you do have a perverted view of marketplace competition.
Shannon did his homework and brought his proposal to us for input of which we've had plenty and he has improved on ST5S and offered a better product to us at lower cost. That's what they do in the east in case you have been in a cave for the last few decades.

The NZ $250 I shelled out on a then cheap ST3 in 2007 was after lots of research which then was a steal as conversion from USD at the time was ~$400 for which today you can buy a fine 4ch DSO !

Not only has Shannon given us a good product at an amazing price he's added features the others don't like upgradable firmware as the product evolves.
For a minute lets consider the BOM of smartweezers and the decades we've been ripped off for a product at even half the price might seem pricey.

But Shannon has had a problem with tips that he hasn't really shared his solution with us, those that offered the support and suggestions to design and build a better product than the several others available.
The A brands don't have these tweezer tip issues and Shannon thought it best to go for fine tips for a point of difference but came unstuck with robustness, something my 15 year old ST3 tweezers has no problem with.

[Hydron]

It seems a little unnecessary to copy the mechanical design quite that closely, but agreed - it's great to have an option that isn't the cost of a decent entry-level scope. Responsiveness is also fantastic compared to the other tweezers I've tried (I haven't used the ST5S or any of the other high end ones though).

Also it seems there is already some funny business going on within Canada with Siborg and LCR Research, some pretty similar products from each of them? (not quite as close a match for the mechanical design as is going on here though).

Does anyone know if the accessories (i.e. tips) are compatible between the "smart tweezers" or the LCR Research stuff and shannon's version?

[tautech]

It seems a little unnecessary to copy the mechanical design quite that closely,.........

Copy ?
It was improved beyond all others for better control of small SMD devices.
You know, those teeny weeny things that you just look at wrong and they are never to be found again.

[Hydron]

Oh, are they significantly better than the ST5x ones that they most closely resemble? Like I said I have not tried the other tweezers of this style, though the ST42s do seem pretty good (they are so much better than the Mastech MS8911s that they're not even in the same league).

In that case I shouldn't have said "mechanical design" if it's really only the industrial design choice that's possibly questionable.

[tautech]

Yeah well we've already had a similar 'why do DSO's all have the same sort of construction'.
As we all well know they all look similar but are quite different once we look harder.

Form factor means little, it's what's inside that counts. 

[ebastler]

Yes well you do have a perverted view [...]
[...]in case you have been in a cave for the last few decades.

Not sure why you see the need for personal attacks here. Do you hold a stake in this as a distributor? Or is this just your usual personal style? I am no longer interested in your opinion, I think.

And if someone could point me to the aspects where the mechanical design was "improved"? Let's call a spade a spade -- as far as the mechanical design and user interface are concerned, this is a plain knock-off of the ST5. Of course that is not illegal, assuming that there are no design or utility patents on those aspects. But it does impact my respect for this "we came up with a much better design than anything that was available before" project.

[thm_w]

EDIT: IdealTek actually seems to be a distributor only; their own expertise is in mechanical tweezers. The actual manufacturer appears to be SmartTweezers in the US, which explains the product name too: https://www.smarttweezers.com/st5s/.

Canada. Here are their previous designs: https://www.smarttweezers.org/
There is also the LCR research: https://www.lcrresearch.com/elite2 with similar designs. Recall there being another one as well..
Regardless, the case is clearly a copy, but the PCB is completely different, if you saw the previous posts in this thread.

Maybe someone can buy the smarttweezer tips and see if they fit the ST42: https://www.smarttweezers.org/smart_tweezers_spare_parts/catalog.html

[KungFuJosh]

That's weird, I've had my ST42 tweezers since last May, and I haven't had any contact issues with the tips. I've used them plenty on SMT and THT stuff.

[tautech]

That's weird, I've had my ST42 tweezers since last May, and I haven't had any contact issues with the tips. I've used them plenty on SMT and THT stuff.

A finer tip was produced and it was too easily damaged.
Carefully read the previous page. 

[KungFuJosh]

That's weird, I've had my ST42 tweezers since last May, and I haven't had any contact issues with the tips. I've used them plenty on SMT and THT stuff.

A finer tip was produced and it was too easily damaged.
Carefully read the previous page. 

Too much effort. At least my tips work. ...also, they're pretty fine to begin with, why would anybody want something tinier? I have no problem testing 0402 with them, and I don't currently have anything smaller to mess with.

[Hydron]

Canada. Here are their previous designs: https://www.smarttweezers.org/
There is also the LCR research: https://www.lcrresearch.com/elite2 with similar designs. Recall there being another one as well..
Regardless, the case is clearly a copy, but the PCB is completely different, if you saw the previous posts in this thread.

Maybe someone can buy the smarttweezer tips and see if they fit the ST42: https://www.smarttweezers.org/smart_tweezers_spare_parts/catalog.html

Looking at the spare parts page shows that the inside of the ST5x case is actually quite different to the ST42 (probably explaining the apparently improved tweezer action - sadly I can't compare it as I only have the ST42), which begs the question of why you'd copy the exterior of the case so closely given the rest of the design is mostly unique. Anyway not a concern given I like the product, just curious as to the decision process, as it does invite some "it's just a clone" criticism even when it's not actually the case.

[KungFuJosh]

Looking at the spare parts page shows that the inside of the ST5x case is actually quite different to the ST42 (probably explaining the apparently improved tweezer action - sadly I can't compare it as I only have the ST42), which begs the question of why you'd copy the exterior of the case so closely given the rest of the design is mostly unique. Anyway not a concern given I like the product, just curious as to the decision process, as it does invite some "it's just a clone" criticism even when it's not actually the case.

The answer I would guess  is that if a quality case design exists and already is being manufactured, that would make the design process and production much less expensive.

[Shannon]

Still I have an impression I often need to grip and press firmly to get a reasonable readout. Is this normal?


Obviously the readouts for low resistance components are not super precise and I can obtain much more stable and precise values with dedicated milliohm or battery meters. But it is absolutely enough for checking the components on the PCBs.

Couple of suggestions/questions:
1. Can you detect open-loop OL. At the moment the unit never detects it, but rather show random high +-2-3GOhm values, I assume this is just some kind of noise being amplified. Can you detect this and show OL instead if the variance of the measurement is too high for anything that makes sense?
2. Can you make press and hold instant (without countdown) turn off? (Similar to how you turn on the device) At the moment in v1.4.4 in my unit it does nothing except beeping. I'd love to have a quick way to turn it off. Of course like you said in the previous posts the timeout should work okay and I should not worry about the battery life etc. But I just have a habit and I like turning off things myself 
3. Can you make the unit beep once when it is turned off, both manually and with timeout?

Btw. Is IdealTek ST-5 some kind of rebranded ST42? It really looks almost the same, except the UI layout being slightly different and price noticeably higher. 

This thread hasn't been updated in a while, and we are late.
we are still here, and we haven't run away 
Thanks for the information so we can make it better.

“Still I have an impression I often need to grip and press firmly to get a reasonable readout. Is this normal?”
1. It is often necessary to use some force to get the correct result during use. The reason is that the tip of the tweezers is gold-plated in order to keep the surface in good contact, but the pins of the components to be tested or the surface of the solder are prone to insulating flux and oxide layers, so if the results do not meet expectations, try to use some force, so I always Opt for extra pointed multimeter leads, even if they tend to break frequently.

“for low resistance components are not super precise”
2. For the measurement of milliohm impedance, we have not stopped thinking about these problems. A few days ago, we tried to use the tip of the tweezers for four-wire measurement. The user experience is not as good as precise tweezers, but the test results are full of imagination. Image attached.

“Couple of suggestions/questions:”
1. Open-loop OL detection, this suggestion is very good. Compared with it jumping around randomly, an over-range prompt will make people feel more at ease.
2. We have received many requests for a long-press shutdown. There will be an update of the code version recently. This function will definitely be launched. After the new version is released, I will tell you in the forum.
3. There is no problem with the implementation of the shutdown prompt sound, we will try to add one. It is true that when we are busy with other things, it often shuts down automatically with only screen prompts, which is not so comfortable.

“looks almost the same”
It looks similar to ST-5 in appearance, but they are entirely different. In terms of structural design, ST42 will be much more stable. This is a user experience that other tweezers cannot provide. Of course, these experiences cannot be seen directly.
Now almost all mobile phones in the world are like iPhones, but an iPhone is an iPhone.
We are also trying to make an elegant product from the inside out

[Shannon]

Regardless, the case is clearly a copy, but the PCB is completely different, if you saw the previous posts in this thread.

Looking at the spare parts page shows that the inside of the ST5x case is actually quite different to the ST42 (probably explaining the apparently improved tweezer action - sadly I can't compare it as I only have the ST42), which begs the question of why you'd copy the exterior of the case so closely given the rest of the design is mostly unique. Anyway not a concern given I like the product, just curious as to the decision process, as it does invite some "it's just a clone" criticism even when it's not actually the case.

We will find some surprising coincidences in our lives. For example, I often find that the heights of tables are surprisingly similar, and the widths of door frames are also similar. These details often make me feel that there is a mysterious force lurking around us, formulating our plans with some rules .

When we design, a big premise is that the structural design must be strong enough, but they are either like real tweezers, two pieces of tweezers arms are welded together, or parts are used to lock the arms of the tweezers together. Then for small batch production, it is difficult for us to avoid manual work, and welding is not so convenient, so we choose the second method, and then the front end of the tweezers looks like ST5S.

A premise of the second half of the design is that there is a mass-produced and reliable screen with a suitable size. Then we found that the price and quantity of the screen can easily meet our needs. We also planned ABS housing for the color screen, but for time reasons, was not implemented. image attached.

But I truly agree with your feeling, cause "If it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck."