The Open.Theremin.UNO is based on open source software running on the Arduino. On this site you find variations of the standard theremin software. Some of them might need modifications to the board or be in experimental stage.
Feel free to explore.
Volume and Wave Switch for Extension Kit V2.0
Use this software to add the wave table switching and volume control to the Open.Theremin.UNO V2.0 with extension kit installed.
The following software packages were developed and provided by Daniel Franzen. Many thanks, Daniel for this amazing Extension to the open theremin.
Open Theremin Master CV & MIDI
Use this software with the Open.Theremin.UNO shield to expand it's functionality to output control voltage and MIDI over USB.
Open.Theremin.UNO Extension CV & MIDI
Use this software with the Open.Theremin.UNO with Extension Kit V2.0 to expand it's functionality to output control voltage and MIDI over USB.
For details on the implementation and instructions see here.
Polyphonic Theremin for V1.2
Turn your open.theremin.uno into a two pitch antenna, polyphonic theremin. All you need to do is update with this software. No hardware modifications are required. Eventually you want to replace the volume antenna by a second straight antenna. For a demonstration see video here: http://www.youtube.com/watch?v=lHeZW5QNamY&feature=share&list=UUze-aBdbS0B_oJMPvCs85dA
Volume and Wave Switch for V1.2
Code to add a volume knob and a switch to choose between multiple wave forms by Yasushi Yoshida. For the hardware modification please read the code and see here.