The PING))) ultrasonic sensor is perfect for any number of applications that require you to perform measurements between moving or stationary objects. The sensor measures distance using sonar; an ultrasonic (well above human hearing) pulse is transmitted from the unit and distance-to-target is determined by measuring the time required for the echo return. Output from the PING))) sensor is a variable-width pulse that corresponds to the distance to the target.
Parrallax 910-28015A PING))) Ultrasonic Sensor + Mounting Bracket
When coupled with the Mounting Bracket kit the PING))) sensor can make a 180° sweep of its environment and determine its course. Together they're great for autonomous navigation.