Bats fly back and forth in a cave at night to find their food. While flying at night, a bat emits squeaks that reflect off the walls of caves and flying insects. These squeaks return to the bat's nervous system and are used as clues to determine the location and shape of the objects. The bat can tell where the next meal is and when to avoid other objects.

A motion sensor (also called an ultrasonic detector) uses technology for a similar purpose. A motion sensor uses a motion detector that sends out high frequency sound waves to a target object and waits for the sound wave to come back. The motion sensor measures the time needed for the wave to leave and return to the detector. What is so unique about a motion sensor is that software can determine and display the distance a wave covered based on the speed of sound in a graph.