Here’s a really cool DIY showing you how to build a hard disk laser scanner made from bunch of old hard disks.
My latest tinkery hardware and embedded systems project is a homebrew laser scanner. You know, the kind you see at planetariums- sweep a laser beam around on the wall really fast, and draw vector graphics. Commercial laser scanners have been around for decades now, but buying a complete system is still really pricy, even on eBay. Besides, where’s the fun in that?
There are plenty of examples of homebrew laser scanners on the internet. Many people have wired up a pair of loudspeakers, hard disk actuators, or other readily available mechanisms to an amplifier and used them for simple laser graphics. This will make some pretty wiggly patterns on the wall, but it isn’t a real vector graphics display. The best example I know of for a totally built-from-scratch laser projector (not using commercial galvo actuators) actually uses custom hand-wound galvanometers. Very nice.