This battery powered electronic musical instrument is a descendant of the theremin and can be played without contact from the musician. This small instrument contains two infared (IR) sensors that measure proximity. One sensor controls the note, while the other controls the octave that is played through the speaker in the front. The tone is reflected by one of seven colors that illuminates the center area and highlights a small indicator located on the top panel. Check out the video.
I have posted the source code, some videos and pics as well, check out the original post.