[Aaron] calls this project “Stochasticity”. It uses two sponges as a musical interface. The performer wears a wrist strap and then draws on the table with water from the sponge to play different notes. You really need to watch the video to fully understand what’s going on here.
We’re guessing that this is Arduino based since some of his other projects are as well. You can try out another quick project of his, an Arduino electromagnetic field detector. Check out video of that after the break.