An ultrasonic sensor is a device that measures the distance between two objects using high-frequency sound waves. “Ultrasonic” soundwaves are those with a frequency of 20 kHz or higher. Average ultrasonic sensor range is between 20 kHz and 1 MHz.
- Piezoelectric components are used for the emitting and receiving transducer
- An applied voltage causes the piezo element to begin vibrating.
- The vibration produces high-frequency sound waves (transmitting mode)
- These impulses are reflected by the target – Echo returns (receiving mode)
- By measuring the time of flight the echo takes to return, the distance can be calculated by using the speed of sound in air. (time-of-flight measurement)
- s =(t ∗c)/2 with c=344 m/s (air)