Ultrasonic sensors are used for noncontact proximity, object detection, and distance measurement. As the name suggests, these sensors use ultrasonic waves as a source to detect the object and its distance. The sensor measures the distance to an object by calculating the time between emission and reception of ultrasonic waves. Ultrasonic waves are very accurate over a short distance and do not create disturbances as they are inaudible to human ears.

The sensor has both an ultrasonic transmitter and receiver. The sensor works on the same principle as that of sonar/radar, which evaluates the presence of an object by listening to the echo of sound waves or radio waves reflected from the object. The sensor emits a burst of high frequency, short-wavelength ultrasonic rays, which when echoed back from the object are received at the sensor. The time difference between...