A prototype RADAR flashlight that can detect a human's presence through walls and doors should one day make law-enforcement officers' jobs safer. The patent-pending device uses a radar and a specialized signal processor to detect movement by discerning respiration from up to 3m away. No physical connection exists between the subject and radar. The development is part of a family of technologies that also detects heartbeat, according to Gene Greneker, a principal research scientist at the Georgia Tech Research Institute (GTRI). "Based on respiration signature alone, the flashlight allows us to detect a stationary individual behind a solid wooden door, or standing four feet behind an eight-inch block wall," Greneker explains. The device uses a narrow radar beam of about 15 to 20 degrees to detect body movement generated by breathing. E-mail [email protected],