Could You imagine doing the “Macarena” in the middle of the Street to control your Devices, like say an iPad? Well NEC can, See Video for Details.
@TatWza

You can tap your arms in different places to control volume or skip tracks. The system relies on a wrist-borne accelerometer that detects the impacts. NEC expects to have this tech built into a watch-like device sometime within the next two years.