Sean Harrison has built a very cool hard drive project. Similar to the Hard Drive Oscilloscope but uses two hard drive voice coils instead of just one. This allows the unit to draw an X/Y image without needing to control one axis by hand.

“Right, well I had been looking around the net and found the Hard Drive Laser Oscilloscope over at Hacked Gadgets and thought about trying to make one using two hard drives to give horizontal and vertical beams. So rather than an oscilloscope it would give me some funky visuals fx.

Similar to the Hard Drive Laser Oscilloscope, But this project uses two hard drives, to project the laser in both the X and Y Axis, Making Funky Laser FX Which move to you music collection. (Pictures and Videos After Link) All You need is a couple of dead hard drives, A Laser Pen few bits of wire, 2 bits of mirror and loads of hot glue!”

http://hackedgadgets.com/2006/06/01/making-a-hard-drive-laser-oscilloscope/