This is a pretty simple, clever way of controlling sound by creating these pins wheels with holes in them that spin over light sensors and change frequency and modulation as light levels change. Different wheels can be swapped out.
SpinTronic, light-based sound controller
Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. And he has a new best-of writing collection and “lazy man’s memoir,” called Borg Like Me.View more articles by Gareth Branwyn