A fun project to build a theremin with an Arduino-based system. My ultimate goal is to build it into a standalone PCB with an independent ATMega at the control. The source code is stored in the arduino-source directory and schematics are in the Eagle file format in the schematics directory. The project is discussed at the GeekDad Community website.
The original Arduino source code and oscillator schematics are based on:
Additionally, I am looking at using a low-pass filter and DDS technique based on: