Hi there, Arduino People!
Visual:Drumset is my newest Arduino project. With it, I won the Prix Ars Electronica Golden Nica 2013 in the category u19 - Create Your World. I used Processing for visualizing percussion beats right on a set of drums, based on Projection Mapping. I also used the Android Mode of Processing to create an app that can modify the visuals on the drums via Bluetooth.
The hardware I used was an Arduino Uno and piezo vibration sensors.
Check it out at http://drum.dominikkoller.net/ (Sorry, the website is currently in German only. The setup-video has English subtitles, though. Just enable them in the youtube player.)
http://www.aec.at/aeblog/en/2013/05/16/die-goldene-nica-fur-visualdrumset/ (This one is in English)
Let me know what you think!