Radar is a detection system that uses sound waves to measure shape and distance.
A device developed by Lawrence Livermore National Laboratory to monitor laser technology amounts to a bat brain-sized radar device now available at hardware store costs. The price is expected to decrease. The radar chip sends out electrical pulses at 50 trillionths of a second and then receives the echoes on a patented receiver which can detect echoes reflected from objects at distances up to 200 feet. The device offers tremendous accuracy at low power. Soon to be on the market are hand tools which use the device, including a detector for locating steel within concrete.