Project Soli has developed a 5x5mm radar sensor that tracks sub-millimeter motions at high speed and accuracy. It fits onto a tiny small chip which can be built into small devices for all sorts of objects. This might be the next step in interface design for musical instruments and interfaces for controlling audio.

It’s still early days for Project Soli, but it’s got the crowd here at Google I/O excited. Rather than go hands-free, Project Soli makes your hands the UI — which may already  be cooler than voice control ever was.— The Next Web

I am feeling this one definitely.