Ultrasonic sensors operate on the p

Ultrasonic sensors operate on the principle of measuring the time between sending usually a few very short pulses and receiving the reflection of the transmitted signal. The basic building blocks are the transmitter and receiver. Transmitter block may be composed of two types of transducer: Magnetostrictive transducers - are working at low frequencies and their principle is based on a mechanical change in the length of magnetic material. Piezoelectric transducers - operate at high frequencies and the principle is based on the inverse piezoelectric effect. Ultrasonic receiver is based on the principle of the transfer of mechanical waves reflected back to an electrical signal.