Therething: Open source MIDI Theremin thing

Arduino Music Technology
Therething: Open source MIDI Theremin thing

The Therething is an open source MIDI controller based on an Arduino. OK, so it’s not a true analog Theremin, but it sounds pretty good, and it’s enclosure is awesome! Check out the link for more information, including the source code and more videos.

Ultrasonic sensors are used to return a distance value, from the sensor to the player’s hand. This value is converted by an Arduino or other microcontroller into a MIDI key value and is output at the correct baud rate (31,250 bps) onto a serial pin. Since MIDI needs a signal to turn off a key pitch as well as a signal to turn it on, it is recommended that when the note changes, two MIDI signals are sent – one to turn off the previous note and one to activate the required note. It may be possible to program some sort of delay/sustain effect in here, so that the off signal is delayed. This would mean that note changes are not too abrupt as there could be a slight overlap between notes.


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4 thoughts on “Therething: Open source MIDI Theremin thing

  1. DJ Ir0nGruve Drinkus Partius Maximus says:

    I’d love for someone to make a kit out of this. The linked material has a lot of info but I don’t feel comfortable building one without at least a parts list and circuit board pattern

    1. Toby Cole says:

      We didn’t realize there was going to be so much interest in the controller before we’ve even finished it :)
      We’re still waiting on the PCBs we designed to come back, so we’ll be updating the docs and building instructions once they turn up.

      Hopefully, once we’ve figured out the best way of building it, we’ll put together some kits. I’d imagine we’d try and get a list of people together who’re interested first then try and buy parts in bulk.

      Also, I gave a 15 min talk about the Therething at a £5 app geeky xmas party last week, all the talks are available online:
      (or if you want to go straight to the therething talk, it’s on vimeo:

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