Ricocheting Radio Waves Monitor the Tiniest Movements

Infrared motion detectors can cover only a limited amount of space, a person has to be within the detector's line of sight to be detected, and lights can go off when a person remains still for too long. Work has demonstrated that patterns made by radio waves can detect a person's presence and location anywhere inside a room. A new motion sensor based on metamaterials is sensitive enough to monitor a person's breathing.