Tiny optical theremins


Matrixsynth pointed out a couple incredibly small optical theremins that look like they’d make for a great afternoon project. [AlexArt] first built the simple circuit on a piece of protoboard (Google translated). Knowing he could go smaller, he then built it freeform with a buzzer instead of a full size speaker. The design is based around the common 555 chip and photoresistor. Here’s a simple circuit you can use to lay out your own. The optical theremin should not be confused with the traditional RF theremin since the name comes from the similar sound, not similar construction.

16 thoughts on “Tiny optical theremins

  1. I made one of these for a project; I used the schematic on the last link, but I translated it to use on a breadboard. It worked well, and it makes awesome sounding square waves.

  2. This is pretty sweet, very low parts count too. This is by far the simplest theremin (if you can still really call it that) that I’ve seen. Good find.

  3. Neat toy, good project, looks like fun, but it’s not a Theremin. At all. Not even kind of.

    Anybody out there have insights into actually constructing a Theremin? It would be really interesting to a lot of folks here I’m sure. I’d really love to see how to build one at any rate!

  4. do a google for “theremin schematic”. and as i see it, a theremin is an oszillator with a touchless frequencycontrol, which this little project offers.

  5. It takes a pair of analog oscillators heterodyning, not just one, for the frequency control. Its raw and messy, as the different harmonics you >don’t< intend from the interaction of the analog coils is what makes the warm signature sound of a theremin. Digital square waves don’t work for that and make for a lousy emulation. There is also the touchless volume control on a Theremin through a similar setup, and that isn’t even attempted to be emulated.

    Again, cool synth/noisemaker/whatever. Not a Theremin though. Might as well just call it a guitar or a cell phone. They all make noise so they are the same thing, right?

  6. Careful man, those Theremin guys will cut you if you even pretend to emulate a Theremin and call it by the only name you could possibly reference.

    They’re mean and quick with the sharp steel!

    Beware!

  7. The Frostwave Spacebeam Theremin and CV controller is a developed version of something similar, that has been around for a while now. For potted Theremin history and Spacebeam overview see;

    http://www.frostwave.com/spacebeam/

    @stunmonkey – It’s cute to make it very simple, but the real trick with theremin design is to make it *controllable* by a *musician*. /elektor/ published a design (and discussion) that, while pretty complex, looks ‘safe’ for performance work.

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