Transducers Part 4 - ultrasonics

Hello, is the common shout by many to see if they get an echo coming back from an object or objects. The action of shouting of hello creates vibrations of the air that travel outwards much like the action of a pebble dropped into a pool of water. If the tiny ripples of water created by the pebble hit a solid object then they change direction much like light hitting a mirror. Sound waves produce a similar effect and that is what we call an echo.

Sound is a name of vibrations that we can actually hear, whereas much higher vibrations we perceive as visible light. So there is an whole spectrum between sound we hear and the light we see. The name given to vibrations that are just above most human hearing is called ultrasonic.

No doubt your mind will have already used neural pathways to bring up how bats use ultrasonics to avoid objects and some of you may also be picturing the scan of you before you were born.

The piezoelectric effect is used for the transmitter and receiver. In the simplest form an ultrasonic frequency is sent in short bursts, then the echo received by the same sensor. Electronics are used to measure the time taken for the pulses to return. The time taken being proportional to distance between the sensor and the object reflecting the ultrasonic frequency back.

Ultrasonic transducers are not just used for distance measurments as later blogs will show