DIY Theremin

in DIY by DP | 12 comments


Erdabyz want’s to build a DIY Theremin. This is a musical instrument controlled without direct physical contact. The device has two antennas which in conjunction with the operators body (representing the capacitance) complete two LC oscillators. By moving your hands closer or farther from the antennas, pitch and volume of the tone are controlled.

My girlfriend is a musician (well, for now she’s a student) and some days ago she came to me saying that a teacher had told the class about some weird electronic instrument that you played without touching it and that was used to make alien sounds for movies. Being the electronics freak I am I automatically knew she was talking about a theremin.

Via the forum.

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  1. Ben says:

    You realise that’s a copyrighted design he’s copied? And Seeed’s going to manufacture it? And not even a single reference (except in the original articles of course) of Robert Moog, the original creator?


    • Filip says:

      There is no such thing as a copyrighted PCBs :), he layed out the entire file himself..Other then that, from what I read in the forum, he is building it for himself/his girlfriend, so no mass production will take place. It’s a cool hack he want’s to build for himself, I don’t think there is anyone that would mind.

    • Ian says:

      If it’s patented then there could be a problem making it for production, but probably not personal use.

      I disagree slightly with Filip though, PCBs and schematics (art) can be copyrighted, but (in the USA) a circuit is afforded protection only via patent. It’s totally legal (in the US) to remake a PCB from any circuit (that is not subject to patent).

    • erdabyz says:

      Well, I’m not planning to sell this, I’ll only make one or two at most and I’ll probably give away the leftover PCB’s. I routed that PCB based on the schematic from those articles, I chose my own components and I’ll design and manufacture the antennas and the wooden box. The original EM theremin article’s pourpose is to teach people how to build their own theremin (it includes everything you need) and that’s exactly what I did.

    • Ryan says:

      Bob Moog invented the synthesizer, Léon Theremin invented the theremin. Bob Moog made theremins too, but he didn’t invent them.

  2. Filip says:

    The device was patented in 1928, that’s !85 years ago, I think 75 years is the limit. I could be wrong though

  3. katjap says:

    Why the sudden worry about this? We reverseengineer things all the time. All of a sudden you’re giving this guy a hard time about re-laying out a device from the 1920′s? If you’re going to get so hardline about it then don’t even think about following datasheet application circuits, no.. instead you must abuse every part you get by randomly attaching passives to random pins. Don’t put a capcitor after your LDO, that’s been part of some patented design, instead thou shall stick an inductor >_>. Goodluck with that.

    P.S. He uses an IC in this so i can just about 100% guarentee this doesn’t infringe a 1928 patent.

  4. Ben says:

    Cool down, guys/galls! First, I never mentioned any patent. Second, no credit was given to the designer of this particular circuit (Moog), which I thought was kinda odd for somebody claiming to know this instrument. Third, this design is still being manufactured by the Moog company. As they are not really a big time operation I though this important to point out.

    • erdabyz says:

      I already told that in the original forum post. I thought that posting a link to the articles my work is deriving from was enough credit for their authors. Anyways, the original article from Robert Moog about the EM theremin is titled “Do it yourself theremin” and its pourpose is to teach people how to build that theremin. It is a fully open design.The Etherwave theremin (the one they’re selling) has basically the same schematic except for some minor tweakings in capacitor values and the usage of fixed+adjustable inductors in the LC oscillators, instead of just one adjustable inductor of a larger value. As I coudn’t find the required large adjustable inductors for the EM theremin I went for the Etherwave schematic. That’s it. Everything else I’ll do will be based on the EM design as that includes information about the case dimensions and the antennas and everything required for building it. I know the theremin and there are lots of different designs out there (Moog’s one is just one of the list). And I chose that particular design because it came in an article titled DIY theremin and because it had ALL the info required.

  5. Ben says:

    I understand that you refer to the EM design, but in the end cloned the Etherwave? I’m sorry but I cannot read your board files, so it’s hard for me to tell.

  6. erdabyz says:

    The only difference between the EM and the Etherwave schematics is that the first uses a single 100uH or 82uH variable inductor for the LC tanks and the Etherwave uses a 47uH variable inductor in series with a 47uH/22uH fixed inductor. Also the LC tank capacitor values vary a little bit. I couldn’t find 100uH variable inductors so I used the Etherwave approach. I think Moog’s philosophy is to let people modify and hack their products, and they encourage DIY (the article where the Etherwave schematic comes from is about how to hack the Etherwave for extra functionality). Also, I expected to spend no more than 50-60€ in the whole project but actually I’m already well past the 100€ barrier and lots of things still need to be done. Potentiometers are expensive, knobs are expensive, good capacitors and inductors are expensive, PCB’s are large…I fear that DIY’ing this thing will actually be more expensive or at least not much cheaper than buying the kit from Moog. So I won’t represent any competece for them xD.

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