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Ultrasonic sensors âare based on the measurement of the properties of acoustic waves with frequencies above the human audible range,â often at roughly 40 kHz . They typically operate by generating a high-frequency pulse of sound, and then receiving and evaluating the properties of the echo pulse. Three different properties of the received echo pulse may be evaluated, for different sensing purposes.
Sound sensors work by mimicking the human body process that involves the ears and signal transmission to the brain. Microphones are sound sensors that convert a sound signal into a voltage or current proportional to the detected signal. They typically have a small diaphragm made of magnets surrounded by coiled metal wire. Sound waves cause the diaphragm to vibrate, which vibrates the magnets and induces a current in the coil.