1. Ultrasonic sensors

1.1 Measuring principle

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.