Ultrasonic sensors

Ultrasonic sensors use a short high frequency acoustic pulse as measuring medium. This is emitted towards e.g. an object which reflects it back towards the sensor as an echo. The time of flight can be used to determine e.g. distance. Ultrasonic sensors are often used in applications where the physical principle of optical sensors reaches its limits, i.e. the detection of transparent objects or liquids. Another typical application is level measurement e.g. of bulk goods from a long distance.