Dalek Voice Modulator v2
Two years ago I started working on an Arduino based ring modulator and managed to get something basic working, but not well enough to install in my Dalek. I came back to this project recently and have finally created a decent version by using an Adafruit Wave Shield and hacking their voice changer sketch to produce a Dalek voice.
I need to find some louder speakers, as you can hear my voice as well at the moment, but I'm pretty pleased with this. Instructions for building this are available here.