Ultrasonic sensors
Non-contact measurement

Ultrasonic distance measurement is based on the time between emission of an ultrasonic pulse and reception of the wave reflected by the object to be measured (figure 1 ).

Depending on the application, the ultrasonic wave is propagated either in air, a liquid or a solid, but the transmission characteristics of these media are very different. The transmission of acoustic energy is much more efficient if the measuring medium is a liquid or a solid, rather than a gas.