Yeah there is a device used to measure speed and power, its rigged into a slightly curved kick shield and the information is fed into a laptop which calculates the info.Its not something I would use at my dojo for my students and I'm not sure what its called or where you could buy one though-I dont think its something you would pick up from a supplier, although they may know where you could get one as its a pretty specialist type piece of kit.
maybe they would have something on youtube?