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

[indman]

Del

[tautech]

So the test mode for Diode/LED is a constant current source which supply excitation current to these components, generally 1mA/2mA, and then measure the voltage drop on LED/Diode.

If you have added the beep capability for measurements, it would be very good to make 1 short beep for silicon diodes with a voltage drop of 0.5-0.7V and 2 short beeps for diodes with a Schottky barrier. This is great for quick testing.

Yes this would be useful for diode identification and much better than just a polarity or short indication that my ST3 does. With these old ST3 models you had to select diode mode whereas I believe ST5 recognises diodes in Auto mode.

[Zlotnik]

Hi Shannon,

I believe that floobydust is right in this question, so many serious tweezers allow you to select the voltage on the measurement pins from 0.1VRMS-1VRMS

This!
Make the excitation voltage selectable, and include also voltages low enough to not turn on pn junctions. This helps with in-circuit component measurements.

Price wise, you'll have to be clear on your value proposition.

Thanks Zlotnik,

That's the other main point! we will support selectable excitation voltage for the different test cases, especially for the PCBA components and pin cap measurement.

How low do you plan to go? In the main spec sheet you specify 0.5V, which is still a tad high. (Think Schottky). The MS8911 goes down to 0.1V. You may not get the excellent accuracy any more, but for in-circuit testing, this is very useful.

Also, I'm not quite sure fully get the value proposition over something like the MS8911 yet. I caught the following
- significantly higher accuracy
- mechanically better tweezers
- LiIon battery, rechargeable via USB-C

All three are nice points, I would like them for sure! It will be very hard to compete with the price point though. The mechanical quality of the MS8911 is okay, the coin cells last forever, and most of the time 2% accuracy of plenty for LCR Tweezers. So 100€$£ will be too much it you already have tweezers.

I think overall usability needs to be killer in your tweezers! That's where the LCR Bridge tweezers like the MS8911 don't shine, and the distance to the more modern / nicer DT71 is bigger specwise.

Personally, I'd really like a well working auto-hold function, as discussed by others. Touch, beep, take off and read.
Maybe include a force/pressure reading into the tweezers to detect when the user is beginning to release the grip?

[Shannon]

So the test mode for Diode/LED is a constant current source which supply excitation current to these components, generally 1mA/2mA, and then measure the voltage drop on LED/Diode.

If you have added the beep capability for measurements, it would be very good to make 1 short beep for silicon diodes with a voltage drop of 0.5-0.7V and 2 short beeps for diodes with a Schottky barrier. If the diode is short and there is no voltage drop, then a continuous sound signal. This is great for quick testing.

Thanks indman

it's a good idea, we will try to implement this function by modifying firmware, add some notice mode that may be better for the user.
when a user has a headache about the bugs on PCBA, it's better to inform him by sound, without staring at the screen, just keeping the eyes on the tweezers' tips and components could make the user comfortable.

Continuity Check would be considered as well, eg. When the resistance is less than approx.30Ω, the Buzzer is sounded

[SilverSolder]

So the test mode for Diode/LED is a constant current source which supply excitation current to these components, generally 1mA/2mA, and then measure the voltage drop on LED/Diode.

If you have added the beep capability for measurements, it would be very good to make 1 short beep for silicon diodes with a voltage drop of 0.5-0.7V and 2 short beeps for diodes with a Schottky barrier. If the diode is short and there is no voltage drop, then a continuous sound signal. This is great for quick testing.

Thanks indman

it's a good idea, we will try to implement this function by modifying firmware, add some notice mode that may be better for the user.
when a user has a headache about the bugs on PCBA, it's better to inform him by sound, without staring at the screen, just keeping the eyes on the tweezers' tips and components could make the user comfortable.

Continuity Check would be considered as well, eg. When the resistance is less than approx.30Ω, the Buzzer is sounded

30 ohm seems a little high for continuity.  Maybe make the threshold configurable?  It is one of those things that depend on what you are doing...

[indman]

Del

[Shannon]

Hi Shannon,

I believe that floobydust is right in this question, so many serious tweezers allow you to select the voltage on the measurement pins from 0.1VRMS-1VRMS

This!
Make the excitation voltage selectable, and include also voltages low enough to not turn on pn junctions. This helps with in-circuit component measurements.

Price wise, you'll have to be clear on your value proposition.

Thanks Zlotnik,

That's the other main point! we will support selectable excitation voltage for the different test cases, especially for the PCBA components and pin cap measurement.

How low do you plan to go? In the main spec sheet you specify 0.5V, which is still a tad high. (Think Schottky). The MS8911 goes down to 0.1V. You may not get the excellent accuracy any more, but for in-circuit testing, this is very useful.

All three are nice points, I would like them for sure! It will be very hard to compete with the price point though. The mechanical quality of the MS8911 is okay, the coin cells last forever, and most of the time 2% accuracy of plenty for LCR Tweezers. So 100€$£ will be too much it you already have tweezers.

I think overall usability needs to be killer in your tweezers! That's where the LCR Bridge tweezers like the MS8911 don't shine, and the distance to the more modern / nicer DT71 is bigger specwise.

Maybe include a force/pressure reading into the tweezers to detect when the user is beginning to release the grip?

Thanks Zlotnik

Actually, we plan to use 0.5Vpp as the low voltage excitation, so the Vp would be 0.25V which may defend the measurement from the Schottky diode. add more voltage options would be a better choice, we will consider that.

using force/pressure sensor to detect user behavior may cover the SMD test mode, and these tweezers could test through-hole components as well, there may no force on the tweezers' arm at that time
and we could detect the user behavior by value measurement, most of the time, when the customer finished the test, the measured result would be very close to open.

I have no idea about the mechanical quality of MS8911, but we have confidence in doing better

for the tool selection, I think different people have different tastes and habits.
some people choose those "could work" tools, some people choose those "high performance and high quality" tools.
I have two 6.5 DMM, and I enjoy the user experience
If we use a good tool for many years, the cost is not a problem, but we got a better mood every time.

And I admit that MS8911, DT71, and many DIY impedance tweezers could meet most of the daily requirements, like the 3.5 digits handy DMM and 50Mhz analog oscilloscope.
But we still want to use better tools during daily work.

We have much much higher cost performance than the high ends SMD tweezers, that's what we believe

and do you have MS8911, could you kindly help us conduct an experiment? try to make the tips move in the Y-axis, which would show the stability of the tweezers mechanical design, as I post.

[Shannon]

So the test mode for Diode/LED is a constant current source which supply excitation current to these components, generally 1mA/2mA, and then measure the voltage drop on LED/Diode.

If you have added the beep capability for measurements, it would be very good to make 1 short beep for silicon diodes with a voltage drop of 0.5-0.7V and 2 short beeps for diodes with a Schottky barrier. If the diode is short and there is no voltage drop, then a continuous sound signal. This is great for quick testing.

Thanks indman

it's a good idea, we will try to implement this function by modifying firmware, add some notice mode that may be better for the user.
when a user has a headache about the bugs on PCBA, it's better to inform him by sound, without staring at the screen, just keeping the eyes on the tweezers' tips and components could make the user comfortable.

Continuity Check would be considered as well, eg. When the resistance is less than approx.30Ω, the Buzzer is sounded

30 ohm seems a little high for continuity.  Maybe make the threshold configurable?  It is one of those things that depend on what you are doing...

No problem, we collect another good idea

[Shannon]

I am afraid that if Shannon implements all the good ideas that the participants suggested to him, then the cost of such tweezers will be much higher than ST-5S Pro! This is,of course,a joke,but there is some truth in it.

For the requirements and features, users always have better ideas than those designers.
So professional people do professional things.
I open my mind to collect user's requirements to optimize the design, and you will enjoy the product with functions defined by yourself.

[indman]

Del

[SilverSolder]

So professional people do professional things.

Well then, for complete happiness and a complete set, this tweezers would be very useful to be able to communicate with a PC or Android, as well as output and save measurement results on a larger display.

Just not Bluetooth, pleeeease! 

[Shannon]

So professional people do professional things.

Well then, for complete happiness and a complete set, this tweezers would be very useful to be able to communicate with a PC or Android, as well as output and save measurement results on a larger display.

Just not Bluetooth, pleeeease!

Well, BlueTooth is not in consideration at present, at least this version 

[SilverSolder]

So professional people do professional things.

Well then, for complete happiness and a complete set, this tweezers would be very useful to be able to communicate with a PC or Android, as well as output and save measurement results on a larger display.

Just not Bluetooth, pleeeease!

Well, BlueTooth is not in consideration at present, at least this version 

A possible solution might be wifi, so you could use relatively standard ways to access the data e.g. FTP and/or HTTP.  That opens the possibility for users to relatively easily write their own software to pick up the test data (as a CSV file for example), and a simple and clean HTTP web page means any device can see the data - Android, IOS, PC, Linux...   -   the key to make this useful and practical is to keep it simple, keep it standard...  (and a big enough battery!).

[Zlotnik]

How low do you plan to go? In the main spec sheet you specify 0.5V, which is still a tad high. (Think Schottky). The MS8911 goes down to 0.1V. You may not get the excellent accuracy any more, but for in-circuit testing, this is very useful.

Actually, we plan to use 0.5Vpp as the low voltage excitation, so the Vp would be 0.25V which may defend the measurement from the Schottky diode. add more voltage options would be a better choice, we will consider that.

Ah! I missed that you specified it as Vpp.
The MS8911 output 0.1Vrms, so 0.28Vpp. I'd prefer <0.4Vpp, but 0.5Vpp should suffice for most cases.
What do you mean with Vp=0.25V, btw? You would always apply the full voltage swing, so if the potential between the tweezers is sufficient to turn on a junction, well, you turn on the junction.

Maybe include a force/pressure reading into the tweezers to detect when the user is beginning to release the grip?

using force/pressure sensor to detect user behavior may cover the SMD test mode, and these tweezers could test through-hole components as well, there may no force on the tweezers' arm at that time and we could detect the user behavior by value measurement, most of the time, when the customer finished the test, the measured result would be very close to open.

Yep, sure. It would only make sense to include a pressure sensor if you can pull it of cheaply. Makes no sense to include a 10€ strain gauge. Maybe if you went the DT71 route with magnets instead of springs, you can include a hall-effect sensor?

Anyway, it could very well work reliably just by looking at the measured values: look out for when there's a stable non open-contact value for eg 0.5s, beep, and display median of this 0.5s measurement until the next stable non open-contact value is seen by the uC.

Just don't do it like on the MS8911: they have a button you have to press to hold the value. Pointless. If I can take my other hand to press the button while applying the tweezers, I could just as well read the value.

Coming to think of it, the simples and most flexible implementation would be a button that you can easily press while operating the tweezers. That would be something!

for the tool selection, I think different people have different tastes and habits.
some people choose those "could work" tools, some people choose those "high performance and high quality" tools.
I have two 6.5 DMM, and I enjoy the user experience
If we use a good tool for many years, the cost is not a problem, but we got a better mood every time.

And I admit that MS8911, DT71, and many DIY impedance tweezers could meet most of the daily requirements, like the 3.5 digits handy DMM and 50Mhz analog oscilloscope.
But we still want to use better tools during daily work.

Couldn't agree more! At work, tools (at least on this level) are not what's costly, it's time. At home, this is a hobby for me. If my tools give me more enjoyment doing my hobby, great.

However it's always a question of do I need another tool X. This is where you'll have to compete against whatever people already have at home/work. Here you have to make clear why your tweezers are just so much better, that you have to get them 

We have much much higher cost performance than the high ends SMD tweezers, that's what we believe

Great! I don't doubt that at all - but I think it needs to be clearly communicated what's the appealing package. Eg accuracy better than the tolerance of your passives, premium mechanics, UI though out by engineers for engineers. Nice!

BTW, the higher accuracy is actually nice, as this would allow you eg to bin values and make use of lower-tolerance passives you have lying around.

I have no idea about the mechanical quality of MS8911, but we have confidence in doing better
[...]
and do you have MS8911, could you kindly help us conduct an experiment? try to make the tips move in the Y-axis, which would show the stability of the tweezers mechanical design, as I post.

Sure!
The MS8911 really aren't anything to write home about mechanically. Where my "good" tweezers (not premium, these ones happen to come from an iFixit set) flex maybe 0.1mm in y, the MS8911 flex an easy 1mm or so.
No doubt you can do better! The MS8911 don't exactly feel like premium tweezers. All plasticky and stuff.
They are however still good enough to easily grab 0603. 0402 works as well, but starts to feel a bit off, like picking up a bone china cup of tea with oven mitts.

HTH,
Alex

[Zlotnik]

So professional people do professional things.

Well then, for complete happiness and a complete set, this tweezers would be very useful to be able to communicate with a PC or Android, as well as output and save measurement results on a larger display.

Just not Bluetooth, pleeeease!

Well, BlueTooth is not in consideration at present, at least this version 

A possible solution might be wifi, so you could use relatively standard ways to access the data e.g. FTP and/or HTTP.  That opens the possibility for users to relatively easily write their own software to pick up the test data (as a CSV file for example), and a simple and clean HTTP web page means any device can see the data - Android, IOS, PC, Linux...   -   the key to make this useful and practical is to keep it simple, keep it standard...  (and a big enough battery!).

If you end up using eg an ESP32 as uC, you'd get that for free. Have a "live display" web view. Bonus points if you open-source your firmware for tinkerers to tinker, as the DT71!

[SilverSolder]

[...]
The MS8911 really aren't anything to write home about mechanically. Where my "good" tweezers (not premium, these ones happen to come from an iFixit set) flex maybe 0.1mm in y, the MS8911 flex an easy 1mm or so.
No doubt you can do better! The MS8911 don't exactly feel like premium tweezers. All plasticky and stuff.
They are however still good enough to easily grab 0603. 0402 works as well, but starts to feel a bit off, like picking up a bone china cup of tea with oven mitts.

HTH,
Alex

The MS8911 is an amazing product for its price point - it strikes an impressively good balance between quality, features, and price.  They did a nice job.   

To be worth twice or more of the cost of a Mastech, an alternative product will have to be a work of art! 

[tautech]

The MS8911 is an amazing product for its price point - it strikes an impressively good balance between quality, features, and price.  They did a nice job.   

They needed to as their previous product was a POS even compared to my now ancient ST3 from 2007.
I've seen a few rave about the later 8911 but maybe they have never used an A brand SMD tweezer. 

Shannon knows what's required and will likely present us with a top class product.

[Shannon]

How low do you plan to go? In the main spec sheet you specify 0.5V, which is still a tad high. (Think Schottky). The MS8911 goes down to 0.1V. You may not get the excellent accuracy any more, but for in-circuit testing, this is very useful.

They are however still good enough to easily grab 0603. 0402 works as well, but starts to feel a bit off, like picking up a bone china cup of tea with oven mitts.

haha, Good metaphor!

Thanks a lot for your comments, which help us understand the needs of a number of users, and consider the possibility of middle-end requirements 

we try to make it best and then wait for the people who like it.

[Shannon]

[...]
The MS8911 really aren't anything to write home about mechanically. Where my "good" tweezers (not premium, these ones happen to come from an iFixit set) flex maybe 0.1mm in y, the MS8911 flex an easy 1mm or so.
No doubt you can do better! The MS8911 don't exactly feel like premium tweezers. All plasticky and stuff.
They are however still good enough to easily grab 0603. 0402 works as well, but starts to feel a bit off, like picking up a bone china cup of tea with oven mitts.

HTH,
Alex

The MS8911 is an amazing product for its price point - it strikes an impressively good balance between quality, features, and price.  They did a nice job.   

To be worth twice or more of the cost of a Mastech, an alternative product will have to be a work of art! 

WE ARE THE ARTIST

I believe the key to success is the art of balance.
MS8911 got a nice balanced point, we will get another balanced point as well

[SilverSolder]

The MS8911 is an amazing product for its price point - it strikes an impressively good balance between quality, features, and price.  They did a nice job.   

They needed to as their previous product was a POS even compared to my now ancient ST3 from 2007.
I've seen a few rave about the later 8911 but maybe they have never used an A brand SMD tweezer. 

Shannon knows what's required and will likely present us with a top class product.

I have never used anything better than the 8911, but I have used worse!

[Shannon]

So professional people do professional things.

Well then, for complete happiness and a complete set, this tweezers would be very useful to be able to communicate with a PC or Android, as well as output and save measurement results on a larger display.

Just not Bluetooth, pleeeease!

Well, BlueTooth is not in consideration at present, at least this version 

A possible solution might be wifi, so you could use relatively standard ways to access the data e.g. FTP and/or HTTP.  That opens the possibility for users to relatively easily write their own software to pick up the test data (as a CSV file for example), and a simple and clean HTTP web page means any device can see the data - Android, IOS, PC, Linux...   -   the key to make this useful and practical is to keep it simple, keep it standard...  (and a big enough battery!).

If you end up using eg an ESP32 as uC, you'd get that for free. Have a "live display" web view. Bonus points if you open-source your firmware for tinkerers to tinker, as the DT71!

we considered the wifi and Bluetooth scheme, the decision is hard to make, we believe we could do that, but not yet.

I think recording the test result on PC is a function more suitable for manufacturing factories, such as the ICT application, component inspection, etc.

[Zlotnik]

[...]
The MS8911 really aren't anything to write home about mechanically.

The MS8911 is an amazing product for its price point - it strikes an impressively good balance between quality, features, and price.  They did a nice job.   

To be worth twice or more of the cost of a Mastech, an alternative product will have to be a work of art! 

Yeah, don't go get me wrong: I do like my MS8911! I think they're the lcr tweezers to beat, and Shannon and friends needs to be very clear why their tweezers are better, if they want to compete at x2 price

But Shannon asked explicitly about the tweezers' mechanical qualities as compared to premium "real" (ie not lcr) tweezers. And there, the MS8911 aren't particularly stunning. No idea how the "better" LCR tweezers on the market compare mechanically.

[Shannon]

The MS8911 is an amazing product for its price point - it strikes an impressively good balance between quality, features, and price.  They did a nice job.   

They needed to as their previous product was a POS even compared to my now ancient ST3 from 2007.
I've seen a few rave about the later 8911 but maybe they have never used an A brand SMD tweezer. 

Shannon knows what's required and will likely present us with a top class product.

I have never used anything better than the 8911, but I have used worse!

come on, you are wealthy SilverSolder, and we are SnPbSolder

try to change your taste once in a while, the steak is delicious, even the bread could make you full

[Shannon]

[...]
The MS8911 really aren't anything to write home about mechanically.

The MS8911 is an amazing product for its price point - it strikes an impressively good balance between quality, features, and price.  They did a nice job.   

To be worth twice or more of the cost of a Mastech, an alternative product will have to be a work of art! 

Yeah, don't go get me wrong: I do like my MS8911! I think they're the lcr tweezers to beat, and Shannon and friends needs to be very clear why their tweezers are better, if they want to compete at x2 price

But Shannon asked explicitly about the tweezers' mechanical qualities as compared to premium "real" (ie not lcr) tweezers. And there, the MS8911 aren't particularly stunning. No idea how the "better" LCR tweezers on the market compare mechanically.

Thanks Zlotnik,

take it easy
I have an assumption in mind now, if we have a similar performance such as MS8911 or DT71 and a similar price with a better user experience, what's going to happen?

[SilverSolder]

So professional people do professional things.

Well then, for complete happiness and a complete set, this tweezers would be very useful to be able to communicate with a PC or Android, as well as output and save measurement results on a larger display.

Just not Bluetooth, pleeeease!

Well, BlueTooth is not in consideration at present, at least this version 

A possible solution might be wifi, so you could use relatively standard ways to access the data e.g. FTP and/or HTTP.  That opens the possibility for users to relatively easily write their own software to pick up the test data (as a CSV file for example), and a simple and clean HTTP web page means any device can see the data - Android, IOS, PC, Linux...   -   the key to make this useful and practical is to keep it simple, keep it standard...  (and a big enough battery!).

If you end up using eg an ESP32 as uC, you'd get that for free. Have a "live display" web view. Bonus points if you open-source your firmware for tinkerers to tinker, as the DT71!

we considered the wifi and Bluetooth scheme, the decision is hard to make, we believe we could do that, but not yet.

I think recording the test result on PC is a function more suitable for manufacturing factories, such as the ICT application, component inspection, etc.

But, having the values list on the PC screen as you pick them up is huge -  you could even pipe that display into something like Google Glass that you wear, so you don't even have to look at the display while working with the tiny parts...