Ultrasonic sensors or transducers work on a principle similar to radar or sonar. Ultrasonic sensors generate high frequency sound waves and evaluate the echo which is received back by the sensor. Sensors calculate the time interval between sending the signal and receiving the echo to determine the distance to an object. Ultrasonic transducers, range finders and optical distance sensors available from Rapid are suitable for a wide range of applications such as remote control devices, robotics, intrusion alarms and energy saving equipment.