If you’d like a pseudo-mechanical way of producing a droning synthesizer sound, [gijs] is your man. He made a small synthesizer out of nothing but an old hard drive and a few components.
Whenever a disk platter is spun manually, the spindle motor inside the drive produces a few out of phase sine waves on its connections. [gijs]’ synthesizer compares and amplifies these sine waves and sends them out to a speaker. The result is a strange droning chiptune-esque arpeggio.
The circuit for the build is soldered directly to the hard drive enclosure Manhattan style. Because the output of the spindle motor produces out of phase sine waves, [gijs] thought it would be a good idea if he could capitalize on some phase interference to alter the timbre of his synth. The entire build is mounted to a wall with hinges to one side so the speaker can be moved around. It isn’t much of a change, but we can here some wave forms cancelling each other out.
Check out the video of the build after the break. There’s also a few audio samples available on the project page.