the water wheel i created shows the speed of a flowing body of water.

Leif Brush replied to my question about how to make a frost printer with a drawing and a description:

Water music: I'm trying out the prototype of a sensor board that lets you connect sensors to your computer. I'm using the Scratch program to make an animation that changes with the changes the sensors detect. I've been trying out attaching tinfoil as the material that will conduct electricity - and have used a Cricket so I can carry it to the Minnehaha Creek to dip into the running water. I also tried it under running and dripping faucets.