Author Topic: Voltset - A Multimeter for Your Cellphone/Tablet  (Read 15206 times)

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Offline DarkStar

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Voltset - A Multimeter for Your Cellphone/Tablet
« on: May 16, 2014, 03:23:17 pm »
Just saw this one pop up on Kickstarter: Voltset - World's Smartest Multimeter for Smart Devices

Not a whole lot on the specs that pop out at me, but could have potential...
--Chris ^_^
 

Offline electr_peter

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #1 on: May 16, 2014, 06:49:21 pm »
Just look at those tiny probes!!! Something like these probes makes your appreciate Agilent/Brymen/Fluke/Pomona silicon cable probes much more.

I don't like the idea of measuring mains with your cell phone, this tiny adapter and tiny probes. Brrr.
I am not sold on higher voltage measurements and safety stuff to say the least.

Keep in mind that this thing is compared to Fluke electrician multimeters. I won't ask anything about CAT ratings...

Other than that, I don't really see much value in this adapter, because:
  • it is not autonomous, you always need smartphone to make it useful. This also makes it somewhat dangerous if app doesn't work - how do you check that your circuit is hot then?
  • Can you really log voltage for long enough with your cell phone? Battery will die and you need your phone back for other stuff
  • This thing is useless without probes - so now you have to haul around smartphone, this device and probes, not very convenient. See discussions in this forum about pocket multimeters - probes are the issue if they are too big or detachable.
  • I don't see any mention of wireless logging or logging to memory card. That would be nice
It has data logger with an app though. But they do not provide any accuracy specs, bummer.

EDIT: From Kickstarter: "Can reach 0.5% with your support from Kickstarter". I would suggest to get a simple pocket multimeter if you want to get something small and convenient with similar or better accuracy (you woud only lose on datalogging though USB cable).
« Last Edit: May 16, 2014, 06:55:59 pm by electr_peter »
 

Offline Mike_VS

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #2 on: May 17, 2014, 12:14:10 pm »
Hey Guys, first of all, thanks Darkstar for taking it up on this forum, it is great to get the discussion going here as well!

To clarify: I am one of the guys behind the project (although not the techie)

Thank you Electr_peter for the elaborate breakdown of what you see as flaws and weaknesses. I prefer to hear the "Negative" points, rather than the positive, as these provide guidance for improvements and opportunity for us to try and address these.

You mention the probes, which we had out for a poll among our initial support base, of which 60% prefered to have banana plugs + attached probes, while only 30% would prefer to have banana plugs only.

So for our prototype we used very simple probes to demonstrate the concept, which in hindsight would make more sense to show better quality probes. We hope with our Kickstarter campaign, to get backer based data to the specifics of the probes to be provided, and adjust to what the majority would like to have.

Also, you can plug in your own pro probes into the banana sockets, if that is what you would like.

We do like the ability to be able to turn your smartphone, tablet, arduino / raspberry Pi or computer into a top grade multimeter, especially for when out in the field doing what we love. So it is important that it can connect to these, and function very well. You are also right that it is not always the best idea to use your mobile phone, which is why we try to make our meter modular. In the sense that you can take Voltset + extension module (either one we make, or you can make your own, if you have the skills). So if you want to log for a long time, ideally we want to give the option to have Voltset + extension module [Bluetooth + USB recharged baterry + SD Card], plugged into a power source to power the USB battery = then the only limitation to your logging is that of the size of your SD Card. Want to incorporate it into a bigger network of things? Think of an extension module with WIFI compabilities, allowing to transfer large chunks of data.

Right, i dont want to sound all too defensive, or trying to make it sound like we know it all. Far from it, this is our idea of bringing it to Kickstarter, to get engaged with guys like you, to make the most awesome solution for all of us. And we really appreciate you taking your time to engage in this.

For the accuracy, we are still tweaking and improving, and while our supplier said that we should be able to have 0.025% accuracy, it all depends on our ability to improve our design to squeeze this out, and up untill now, we have been reluctant to make too specific promises to specs. You and others do raise important questions, that we should go back and reflect on, and see what we can do to better communicate out specifications.

Sorry for the long post, but I hope I addressed the questions so far. Please do try to find more flaws and issues that you think we should address, or possible suggestions!

Thanks, lots and love, Voltset Team - Michael Bruun-Larsen
 

Offline daveshah

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #3 on: May 17, 2014, 12:44:18 pm »
Has no-one seen the immediately obviously hazard if the attached probes and banana plugs are directly connected electrically - if you attach your own probes to the banana plug, then connect them to the mains, all of a sudden the tips of the attached probes are live. Likewise if you connect the probes attached to the banana plug to a high current source (e.g. an unprotected RC Li-po battery) and accidentally short the attached probes - kaboom! I struggle to see how this setup could be considered CAT II, let alone CAT III.

Also, are the inputs isolated from your phone/tablet when using the USB interface?
« Last Edit: May 17, 2014, 12:49:38 pm by daveshah »
 

Offline electr_peter

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #4 on: May 17, 2014, 12:50:23 pm »
Hi there, thanks for joining in.
You mention the probes, which we had out for a poll among our initial support base, of which 60% prefered to have banana plugs + attached probes, while only 30% would prefer to have banana plugs only.

So for our prototype we used very simple probes to demonstrate the concept, which in hindsight would make more sense to show better quality probes. We hope with our Kickstarter campaign, to get backer based data to the specifics of the probes to be provided, and adjust to what the majority would like to have.

Also, you can plug in your own pro probes into the banana sockets, if that is what you would like.
OK, it is your choice to have both integrated and external probes. I would suggest to have banana probe sockets come out to the side (side at the bottom/top/left/right) - some small Fluke meters and clamp meters do this. It is more convenient this way as banana probes are a bit too tall to insert from the top.
Also I would suggest to improve quality of attached probes and make them longer.

However, I think attached probes plus external probes creates serious hazard for the user - both probes are connected in parallel and if one probe is attached to circuit, other one can be touched by user. Very dangerous and unsafe design. There must be some disconnect feature when external probes are inserted.

Did you think about certification for CE, CAT or other standards? KS page only mention that you "designed it safe" without any clarification.
[...]In the sense that you can take Voltset + extension module (either one we make, or you can make your own, if you have the skills). So if you want to log for a long time, ideally we want to give the option to have Voltset + extension module [Bluetooth + USB recharged baterry + SD Card], plugged into a power source to power the USB battery = then the only limitation to your logging is that of the size of your SD Card. Want to incorporate it into a bigger network of things? Think of an extension module with WIFI compabilities, allowing to transfer large chunks of data.
EEVblog users may have enough skills and abilities to make something similar themselves, but is it worth it? If you are really desperate to have semi precision data logger (to SD card or wireless), you can buy cheap multimeter with serial interface (optical or wired) and add cheap MCU with SD card.
Please provide more detailed description of you view on Voltset datalogger and how you can use it.
[...]
For the accuracy, we are still tweaking and improving, and while our supplier said that we should be able to have 0.025% accuracy, it all depends on our ability to improve our design to squeeze this out, and up untill now, we have been reluctant to make too specific promises to specs.[...]
So still no concrete specs and final product. Do you plan to have at least fixed specs by he end of KS campaign?
« Last Edit: May 19, 2014, 07:02:41 pm by electr_peter »
 

Offline Bored@Work

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #5 on: May 17, 2014, 02:50:35 pm »
We do like the ability to be able to turn your smartphone, tablet, arduino / raspberry Pi or computer into a top grade multimeter, especially for when out in the field doing what we love.

Actually, that is what I hate about it. You have fallen into the hipster trap that everything these days needs to be connected to a smartphone. Add a smartphone -> instant coolness.

However, the last thing I want to have when in the field, probably working under pressure, a customer breathing down my neck, is having to fiddle with two devices to make some measurement. I do run out of hands quickly. And while doing a measurement my phone being occupied. Or should I need to phone while doing a measurement, I can't tell my counterpart on the phone the current measurements.

And instead of having to make sure the batteries in the meter are OK, I now have to make sure my smartphone is charged, too. You just doubled the risk of not being able to take a measurement because of some batteries being flat.

I have the feeling you have never really worked in the field, or what you consider working in the field is more like lying in a field of flowers, watching the clouds and waiting for a unicorn to show up.

And why should I carry around a smartphone and half of a multimeter, when I could carry around a smartphone and a real multimeter? And should I really need Bluetooth, I can get a real Agilent multimeter, with realistic safety ratings, and a Bluetooth adapter for it. So your idea is not even new. Not even on small scale level. There is e.g. that mooshimeter thing (also a rather flawed idea). And seed studio with http://www.seeedstudio.com/wiki/Bluetooth_Multimeter is there, too.
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Offline all_repair

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #6 on: May 17, 2014, 04:24:48 pm »
I repel that at first, needing 2 devices to do what a more rugged Fluke can do.  After seeing the video, there are some good points of the meter.  It can be useful for some routine work situation and checking, so help reduce errors in checking and integrating the measurement into the maintenance checklist etc etc
« Last Edit: May 17, 2014, 04:55:23 pm by all_repair »
 

Offline Mike_VS

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #7 on: May 17, 2014, 05:22:19 pm »
Has no-one seen the immediately obviously hazard if the attached probes and banana plugs are directly connected electrically - if you attach your own probes to the banana plug, then connect them to the mains, all of a sudden the tips of the attached probes are live. Likewise if you connect the probes attached to the banana plug to a high current source (e.g. an unprotected RC Li-po battery) and accidentally short the attached probes - kaboom! I struggle to see how this setup could be considered CAT II, let alone CAT III.

Also, are the inputs isolated from your phone/tablet when using the USB interface?

Hi Daveshah and Electr_Peter, you raise a really important question. Dealing with electronics, is not to be taken lightly. Safety is really important, for you, us and in general.

While we have not been good at communicating our the technical features in depth, we actually have solved for the issues you mention. We have a dedicated switch for when you plug in the banana plug probes, that will disconnect the attached probes = no electricity transfered over.

We also have safety isolation in the hardware with re-settable fuse. The electricity will never reach the phone, or you (given you use the device properly).

TL:DR = Yes, safety measures have been designed into it.
« Last Edit: May 17, 2014, 05:25:01 pm by Mike_VS »
 

Offline theatrus

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #8 on: May 17, 2014, 07:10:02 pm »

Has no-one seen the immediately obviously hazard if the attached probes and banana plugs are directly connected electrically - if you attach your own probes to the banana plug, then connect them to the mains, all of a sudden the tips of the attached probes are live. Likewise if you connect the probes attached to the banana plug to a high current source (e.g. an unprotected RC Li-po battery) and accidentally short the attached probes - kaboom! I struggle to see how this setup could be considered CAT II, let alone CAT III.

Also, are the inputs isolated from your phone/tablet when using the USB interface?

We also have safety isolation in the hardware with re-settable fuse. The electricity will never reach the phone, or you (given you use the device properly).

TL:DR = Yes, safety measures have been designed into it.

A fuse is not galvanic isolation.
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Offline daveshah

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #9 on: May 17, 2014, 07:44:45 pm »
There are three ways I can see this being safe:

 1. Supplied with a strict warning about not being used for circuits above 30V, and no CAT rating printed on it
 2. Full galvanic isolation between the device and the phone using an isolated DC-DC converter for power and a digital isolator (such as ADUM4160) or opto-isolator for data, both of which must be rated to withstand the maximum tranisent allowed for the CAT rating
 3. Full galvanic isolation by making the device bluetooth only with its own battery.
 

Offline Gallymimus

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #10 on: May 17, 2014, 09:00:46 pm »
I also have serious concerns about safety.

There are reasons none of the reputable meter manufactures have a USB interface that is not optically isolated. (this product may be isolated but they don't say)

Also you never see resetable fuses in meters.  There is a reason for that too!  I've not seen any PTC (assuming that's what they are using) fuses which have the breaking capacity or withstand voltage for any CAT ratings.

I think it's a fine product idea, but certainly amongst the serious electronics folks, they will be skeptical without careful explanation of the safety features OR a big UL stamp on the device and a filing number!!!

 

Offline all_repair

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #11 on: May 17, 2014, 10:18:35 pm »
Resettable fuse ?
I have been burning a lot of fuses in testing and troubleshooting.  No, I want to keep to old reliable fuse - once blown is blown with no chance of recovery or malfunction.
 

Offline c4757p

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #12 on: May 17, 2014, 10:40:52 pm »
I hope "no galvanic isolation" is just a miscommunication. If you call a non-isolated device a "multimeter" with a "CAT rating", you are a reckless ass who is going to get someone electrocuted. No... that's a complete fail. The only name for a non-isolated "multimeter" is "toy", and that is reckless because some kid will get himself killed on it...

We also have safety isolation in the hardware with re-settable fuse. The electricity will never reach the phone, or you (given you use the device properly).

A resettable fuse is just a positive tempco resistor. Hmm... I must have missed this "safety isolation" feature of resistors in my Circuits and Electronics courses. Perhaps I should re-register for them this fall semester? :bullshit:

Might wanna check the voltage rating on a typical PTC fuse, too.

:-- :palm:


Edit: Yeah, there's no isolation in that thing:




Edit #2: FWIW, this appears to have isolation, at least, until you stick your tongue under the plastic >:D
« Last Edit: May 17, 2014, 11:45:07 pm by c4757p »
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Online fcb

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #13 on: May 17, 2014, 11:00:22 pm »
Mike_VS: Why don't you get the technical bod to head over to this forum and answer questions.
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Online fcb

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #14 on: May 17, 2014, 11:10:42 pm »
Apart from the obvious issue of isolation (it is isolated right?????), the unit is described as a "multimeter" - historically this has meant something that can measure voltage, resistance and current.  I couldn't seen any demos or data on doing this.
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Offline Stonent

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #15 on: May 18, 2014, 08:59:04 pm »
I would find it easier to design with a premade BT module from china than to work out the USB interface.

https://www.google.com/search?q=surface+mount+bt+module&es_sm=122&source=lnms&tbm=isch&sa=X&ei=2h55U_PTCsOMqAbdx4GQAw&ved=0CAkQ_AUoAg&biw=1280&bih=709

Those things are pretty cheap and I see them inside other things a lot.
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Offline Mike_VS

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #16 on: May 18, 2014, 10:07:44 pm »
Hey Guys, I realize that I am not the right guy to be answering the questions on this forum, it is way out of my league, and if I were to try and convey the message, i would probably distort the message. Once our guys are back from the Maker Faire in Bay Area, I will make sure to ask them to get here and answer the questions.
Sorry for the delay in response time.

Voltset Team, Mike
 

Offline max_torque

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #17 on: May 21, 2014, 11:16:34 pm »
I think this forum is a good place to get an idea for what sort of features are useful in such a device, as well as a flavour for the sort of safety necessary for it (but ultimately, you WILL have to certify your device to some existing legal standard).

For me, who does a lot of "adhoc" testing, both in the field and at my bench, i find a conventional multimeter the best solution, with it's high safety level (min CATIII) and if worst comes to worst, i haven't nuked my phone, just a $150 multimeter.

But, for someone who is more of a hobby user, where low cost is important, then maybe this device has some uses, although i suspect a completely seperate isolated device, with a decent bluetooth connection and "App" for ones smart phone makes much more sense to me.

I think the problem you will find is that you won't be able to get your device anywhere near the cost of a cheap chinese multimeter.  Lets face it, you're not trying to compete with Fluke here, but some of the more, er, lower end devices!
 

Offline daveshah

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #18 on: May 22, 2014, 12:11:22 pm »
The thing is, in its current state, I would only want to use it with an old phone (and only on low voltage circuits), not my main £400 phone. That makes it practically useless as it means carrying around just as much kit as a normal multimeter, that can't be used on the mains, and also that needs to be recharged every few hours. If this had proper galvanic isolation and UL approval I'd probably buy it.
 

Offline notzippy

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #19 on: May 22, 2014, 03:34:03 pm »
I would find it easier to design with a premade BT module from china than to work out the USB interface.

https://www.google.com/search?q=surface+mount+bt+module&es_sm=122&source=lnms&tbm=isch&sa=X&ei=2h55U_PTCsOMqAbdx4GQAw&ved=0CAkQ_AUoAg&biw=1280&bih=709

Those things are pretty cheap and I see them inside other things a lot.

Agree, wireless would eliminate any threat of damage to the phone. Any decent meter connecting to a pc uses optical isolation. Using bt technology for a phone just makes sense

Nz
 

Offline Nerull

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #20 on: May 25, 2014, 07:45:55 pm »
PTTC fuses will only blow after a high current has started flowing, and they are still conductive even when "blown", just with a high resistance. High voltage will still be present.

 I cannot find the actual tests used for CAT ratings, but at least one datasheet lists a 600V cat rating as able with withstand 6kV transients. What do you think will happen to your meter if exposed to 6000V? The highest rated PTTC fuse I can find has a 600V absolute maximum rating, with time to trip measured in seconds. If you try to get that CAT rated they will laugh you out of the building.

I don't think those probes will pass a rating either - no shield to keep your fingers away from high voltage. Looks like rounded tips too, better hope your circuit doesn't have any oxidation.
« Last Edit: May 25, 2014, 07:53:37 pm by Nerull »
 

Offline corrado33

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #21 on: May 26, 2014, 05:10:30 pm »
From the kickstarter, it looks like this will be sold for ~$100 US. For that much money, I'd much rather buy the winner of the $100 shootout (or two of the $50 shootout) meters. Sure, they're a bit bigger, but if you're going somewhere that requires a multimeter, you probably have more than just a multimeter. (Aka parts to fix whatever you're looking at etc.)

Besides, I'd never hook this thing into my phone.

Plus, how durable is this thing? Is it durable enough to be thrown around in a backpack? Sat on? (if it's in your back pocket?) Bounced around in a glovebox? I know a fluke is (as are many other reputable DMM brands.) As much as you think it'd be nice to just mount it to the back of your phone, no one will do that.

Besides, many times I use a multimeter in places where I wouldn't want my phone. In the dirty engine compartment of a car for example, or next to a very hot soldering iron. When I'm working, I don't always want or have my phone beside me. I leave my phone in the garage when I'm working on cars, or in my pocket when soldering.

The only thing that this would be useful for is in an emergency (say in a car). And even for that, a cheap pocket meter would be a better idea.

I don't think this thing stands up to even the cheapest of actual DMMs. (Ok maybe better than the chinese $10 ones, but not by much.) But then again, the $10 ones can measure resistance and current (not well, but they can).

Not a product for me. I bet most EEVBlog viewers will have a similar reaction.
 

Offline miguelvp

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #22 on: May 26, 2014, 11:11:05 pm »
Well, it's going to get funded no doubt.

Probably targeted to the moders/makers. That don't know that it's awkward enough to deal with a DMM that doesn't have a good stand, now they have to deal with two different pieces but I guess if the phone lays flat you can see it fine.

I noticed the picture of the DMM vs the Volset, the Fluke has the cables all mangled the Volset has no proves so it looks cleaner. That's good marketing at work :)
 

Offline corrado33

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #23 on: May 26, 2014, 11:20:44 pm »
I noticed the picture of the DMM vs the Volset, the Fluke has the cables all mangled the Volset has no proves so it looks cleaner. That's good marketing at work :)

I noticed the same thing. Marketing wank is what I imagine Dave saying.
 

Offline echen1024

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Re: Voltset - A Multimeter for Your Cellphone/Tablet
« Reply #24 on: May 27, 2014, 12:44:49 am »
Without isolation, if you decide to measure some transient, your entire phone will be blown to bits and you electrocuted. Not a good idea.  :scared:
I'm not saying we should kill all stupid people. I'm just saying that we should remove all product safety labels and let natural selection do its work.

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