The Hokuyo PBS-03JN Scanning Infrared LED Obstacle Detection Sensor is a less expensive alternative to laser range finders in indoor environments. The operation principle is that a semicircular field is scanned by an infrared LED. The PBS-03JN is able to report obstacles from 200mm to 3000mm in a 178.2° arc (1.8° angular resolution). Its low power consumption, 24V 250ma, allows it to be used on battery operated platforms and is perfect for robotic applications.
PBS-O3JN Datasheet