You probably won't be in demand on the club scene, but you can save yourself the cost of a pair of 1200s with this DIY analog turntable made from discarded technology including a cooling fan and a cassette player.
Created by ITP student Adrià Navarro for their "Stupid Pet Trick" assignment, the cooling fan controls the speed of the playback motor inside the cassette player, facilitated by an Arduino wired in-between. So the faster you spin the fan, the faster the music will play, just like with a record player. To determine how fast the fan is spinning, Adrià simply measures the current it generates, which is then mapped to the speed at which the cassette plays.
The trickiest part was smoothing out the unstable voltage levels produced by the fan, without introducing delays between it and the cassette player which would make it feel unresponsive. While the final results are no where near as interactive as scratching an old piece of vinyl on a record player, we like the re-use/recycle approach taken here. A solid B+ project that's just a glow stick away from earning an A-. [ITP via Make]