Say Watt? A Talking Multimeter?


After a request from one of his friends, [Mastro Gippo] managed to put together a talking multimeter to be used by blind persons working in electronics. He wanted a feature-rich meter that had serial output, and recalling this Hackaday article from a few years back led him to find a DT-4000ZC on eBay, which has serial output on a 3.5mm jack. (Though, he actually recommends this knockoff version which comes with excellent documentation).

It turns out there aren’t many talking meter options available other than this expensive one and a couple of discontinued alternatives. [Mastro Gippo] needed to start from scratch with the voice synthesizer, which proved to be as easy as recording a bunch of numbers and packing them onto an SD card to be read by an Arduino running the SimpleSDAudio library.

He found a small, battery-powered external speaker used for rocking out with music on cell phones and hooked it up to the build, stuffing all the electronics into an aluminum case. Stick around after the jump for a quick video of the finished product!

41 thoughts on “Say Watt? A Talking Multimeter?

          1. True there are cases where free also hits trademark laws, but i can make an exact copy of a Fluke in my own home and never run afoul of the law. (I kinda thought someone would get pedantic about it, since its pretty darn hard to make any kind of trademark law comment without there being “gotchas”, but for most regular people, incl hackers and makers – if you are not selling that one-off copy you are making at home, there is no issue whatsoever).

            Though italian trademark laws could ofcourse be different in that regard.

        1. You confuse “not illegal” with “not getting caught” “or not worth their time pursuing.” There are cases where a one off home made copy of an object, running afoul of copyright and trademarks, do get cease and desists and takedowns and legal threats.

          1. Yes, I am being broad. (In part because I am not a trademark lawyer, so there are plenty of things I don’t know – like you point out “illegal” vs “not enforced”. and in part because even my limited knowledge means that I am aware that it is “not that simple”)

            You can also run afoul of the law by erecting a big golden M in your backyard (I would think). But for the wast majority of cases it will not be a problem.

            If that is partly due to relaxed application of the law against private people, that is fine too, even if it would be better if it were due to “not illegal” instead.

          1. Ah ok. thanks for clearing that up. Then it comes down to how anal the (international) laws are about private projects i suppose – id still say he gets off free in this case, but law have disagreed with me before :-)

          1. No i did not. I was under the understanding they were refereing to this guy now being in the same situation as sparkfun due to his build – which for the reasons i mentioned were not similiar at all (even accepting that you corrected some of it)

            So I guess there is a knock-off multimeter in the video i didnt watch.

            I will stop bothering you guys now and go try getting my humor-o-meter adjusted so I at least make corrective comments on the actual joke being made :-)

      1. Feel free to do so. It’s like NSA spying on US citizen.
        I don’t care. But keep your stupid laws in your own country. (It’s not so that we dont have stupid laws here)
        Where I live I am allowed to build my own Ferrari, Fluke or wat ever. I am just not allowed to sell it.

  1. Besides it’s use by blind persons, there is another situation – When you are probing around constricted spaces, there’s always the chance that you can slip up if you are not keeping a watch full eye on the probe tip. Having the Audio multi meter (AMM?) call out the readings as you move the probe from test point to test point without your having to take your eye off would be as valuable as a buddy calling out the readings.

    1. this. I use a simple tool in my work (automotive) which beeps different tones for 0v and 12v and “plays” the signal if its pwm/audio/canbus etc allows me to go through a loom or aquard connector without having to take my eyes off where im probing. Invaluable when chasing a fault through an ECU/BCM etc Keep meening to make a tone generator that can feed a signal into a wire such that it can be picked up at the other end by the meter for quick identification of a wire on a loom end connector. i know similar devices exist for ethernet/telecoms :)

  2. I’m very supportive of disabled individuals being able to carry out tasks reserved for those with the sense necessary to complete them, but a blind person working on electronics seems about damn near a wild idea. Components are already as small as it gets, and I couldn’t imagine feeling my way around a circuit board. Kudos to a talking meter, more empowering, but I just can’t fathom how they do it at all. I can barely see some of the things on surface mount and I sure as hell will never distinguish a spaghetti mess of traces.

    1. Exactly. I’m all for making things accessible to those with disabilities, but I really can’t imagine how a blind person would work on electronics.

      I guess maybe you could make it work on a breadboard, but keeping track of where and what each component is in your head seems a bit unrealistic, I think. Especially with something as complicated as an MCU. Then you have the problem of ESD while feeling around for the correct pins…

      1. It’s nice to help those who have a impaired vision but I see this better serving for those odd situations where the readout isn’t visible to the user such as underneath a car or crawlspace.

        I dont see any reason why it cant serve both situations, being blacked out blind isnt always the case ;)

        1. In electronics blind means done for. One may be able to probe logic levels and tolerate unceasing mistaken readings, but you won’t be working on flyback circuits anymore. How you going to interpret an o-scope display? You won’t safely work with a final triode beyond a certain point, and then never again. You may be able to teach others by granting them your guidance, and perhaps manage service reps and their billing issues…. but sooner or later you’re out of the game. You could keep going if you were mentor to a bright student, but that’s temporary at best and really one should have been passing the knowledge down long before.

          Fine… let the meter talk to me. You sure I probed the right point or one nearby with higher potential? GF already complains about that. Couple years I won’t be able to see to probe the circuit safely. Cerulean Cataracts. Doc decided Mom needed a big dose of antibiotics back when I was -0.5 yrs of age.

          1. “You sure I probed the right point or one nearby with higher potential? GF already complains about that.”

            Lol. I hope that’s the joke I thought it was.

    2. If I remember correctly, there is a member of the “geiger counter enthusiasts group” who while blind actively does electronics…don’t really understand how, but apparently it’s possible…

  3. You want to know why fluke did what they did, because unlike the paragraph wrote by the ceo’s secretary would have you believe, fluke doesn’t five a guck about the diy community because we are not the target audience.

    1. Blind people have been doing electronics since there was electronics!
      There is a small but noticable market for this talking dmm, not only for electronics
      but for appliance repair automotive etc.
      Surface mount is, so far, beyond any blind tech Iknow about but I’ve built many
      projects with DIP Micros and the like and solder pretty well.
      If you really want to know more, see:
      Read the “soldering series” you’ll probably learn something you didn’t know about proper soldering technique.

  4. I am blind and do tinker with electronics. But a blind friend of mine is even more hardcore into microcontrollers and such. He did all sorts of things on his own such as ultrasonic and even laser ranging devices for wall detection and such.

    Another project of his is a talking multimeter. The project is here:

    There exist 2 units currently. He has one, and guess who has the other? ;-)

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