The idea is to be able to wave your hands in front of the phone camera and produce musical tones. Different musical tones can be played depending on how far away the hand is from the camera. One way to do this is to recognize hand pixels and measure their proportion with respect to total number of pixels in the image. Tones of higher frequency may be played when the hand is closer to the camera and lower frequency tones can be played when the hand is further away or vice versa. We could also use motion detection to produce the same effect. If a hand is waved at different heights in front of the camera the number of pixels that differ in consecutive frames will be higher when the hand is closer to the camera and the pixel difference will be lower when the hand is further away. This assumes that the hand is waved(shaken) identically at all heights. The same effect can be produced if the hand is waved slowly or vigorously at a constant height. We can extend the same concept and use multiple phones that play tones in different frequency ranges. You can download demos here:

<dowload single phone demo>

<download multiple phones demo>
(Use right click + Save as option)

(Click on image to enlarge)

                              

One Phone                                               Multiple Phones