Max Msp, and Ardunio, and Jitter

I googled interactive art, and I am trying to produce a piece of it with my piano.

http://www.youtube.com/watch?v=y-lOAoWcAV8&NR=1&feature=fvwp

I want it so when you play the piano, different films come up, and effects, I know that I have to use a webcam to scan the hammers beating the strings inside the Piano (Diagrams to come soon)

Photos of piano in Progress.

http://cycling74.com/2006/02/06/jitter-recipes-book-1/