An Arduino-based synthesizer from outer space
I built this! The synth is a project for my Embedded Systems course -- you can read the paper for more information (and by more information I mean I wrote 10 pages, so srsly). The beautiful case was made by Ilia (within a few hours...), and the audio signal generating library is by Dzl TheEvilGenius (find the source code here).
The synth is polyphonic, it can play up to 4 voices at once. There are 12 buttons, corresponding to the usual notes on the Western 12-tone equal temperament scale. Using the knobs, you can adjust the waveform (it can play Sine, Triangle, Square, Saw, Ramp, and Noise waves), octave, pitchbend, and modulation. That is, if you don't mess up the potentiometers while soldering everything (which I did... so only the octave knob works reliably).
Click me to to watch a demo!
Here's a schematic:
