Very cool stuff. I like that he does a 10-finger demo near the end of the video. However, the harp gets very noisy at that point :-). I wonder if you can do so

Very cool stuff. I like that he does a 10-finger demo near the end of the video. However, the harp gets very noisy at that point :-). I wonder if you can do something simple with just the iPad camera, with the iPad laying on a table. One could imagine that this wouldn't be that hard, since your ceiling is mostly one color (white/beige). All you would need to detect is the color and shape of your hand. Then, you could blend this "air-harp" gestural expression (dominant hand) with a more physical interaction (taps and swipes) on the iPad surface itself (w/ your non-dominant hand).