RSSKen Moore, a user experience designer at Google, created a very convincing Theremin simulator using a Wiimote and a Roland JV-1080 synth.
I've seen a few Theremin simulators that use accelerometer data, in both Wiimote and iPhone form, but this is the first I've seen that does a good job of recreating an authentic Theremin experience in all its 50s sci-fi awesomeness. Using some IR gloves and the Wiimote's CCD, one hand's horizontal movement controls pitch and the other hand's vertical movement controls volume.
At just $35, the Wiimote is an AMAZING piece of technology. It has an infrared camera in it which tracks the position up to 4 infrared light sources. So I bought a pair of leather gloves, wired up a couple infrared LEDs to 1.5 volt batteries, and poked an LED through the tip of the index finger of each glove.
Then, I connected my Wiimote to my computer (the Wiimote also supports Bluetooth connections): building on top of Brian Peek's Wiimote hacking software library, I wrote a program which detects the two infrared gloves and converts the vertical position of the left hand to volume, and converts the horizontal position of the right hand to pitch. That information is then sent via MIDI to the synthesizer which creates the actual sound.
One of the more interesting possibilities with this setup is that by adjusting the synthesizer, you can use a Theremin-like interface to control a huge number of effects, not just the standard sci-fi sine wave. I wonder if Léon Theremin would approve.
