These devices use ultrasonic transducers to transmit and receive pulses of sound. These acoustic signals bounce off a target and are received back at the sensor. The amplitude of the reflected sound can also be used as an input to the signal processor depending on the sensing algorithm being used. A single transducer can be used for both transmit and receive, or separate ones can be used for certain designs. Echo-location is used in ultrasonic proximity sensors and level sensors.
Proximity sensors detect the presence, absence, distance, and position of an object or person.
ITC has worked with and supplied customers producing proximity sensor systems to detect vehicles, packages, occupants in vehicles, seeds in dispensers, web or belt tension, and many others. Level sensors work the same way except the target is the surface of a fluid or bulk solid contained in a vessel. This is known as continuous level sensing because there are no fixed points at which the level is measured, as in float switches. ITC customers are involved in level sensing of drinking water in aircraft tanks, fuel in vehicle tanks, bulk solids, etc. Ultrasonic transducers are also used in contact measurement type sensors.