Eye Synth OSC is an app that makes music based on velocities taken from your web camera. Here i am demonstrating how it can be used in a multi application context. Here I am using Eye Synth OSC to play strings along with a simple beat and bass line in logic. Osculator is used to convert the OSC messages to midi.
itunes.apple.com/us/app/eye-synth-osc/id428793374?mt=12&ls=1