Hardware in 2011
One Theremin Per Child
An open source project to create a sub-$30, quality theremin. With all due respect for the One Laptop Per Child program (which is awesome and not in any way related), the OTPC acronym can also expand to “Obligatory Theremin Parts Collection”.
The OTPC kit uses two capacitive sensors for pitch and volume, and generates audio using wavetable synthesis. Yes, that is cheating in the world of theremin-building. Two prototypes exist; the third will be the production version: