Based on a classic cereal box toy, this fun "spudmarine" uses a potato and baking powder to make a sub that dives and resurfaces in a pitcher of water.
If you're playing for an audience you don't want to spend your set looking at a screen. See how one musician made this MIDI foot board for performances.
Elektrosluch is a device for listening to electromagnetic fields. It works as a translator of oscillations from electromagnetic domain, through electric domain to audible domain. This is a tutorial on making your own basic version.