sonic distance meter
Acoustic ranging is an instrument that uses the reflection characteristics of sound waves to measure. Generally, ultrasonic waves are used as modulation objects, that is, ultrasonic ranging instruments. The ultrasonic transmitter emits ultrasonic waves in a certain direction, and starts timing at the same time. The ultrasonic wave propagates in the air, and it returns immediately when it encounters an obstacle on the way. The ultrasonic receiver immediately stops the timing when it receives the reflected wave. By continuously detecting the echoes reflected by the obstacles after the generated waves are emitted, the time difference T between the transmitted ultrasonic waves and the received echoes is measured, and then the distance L is calculated.
Since the speed of the ultrasonic wave in the air is greatly affected by temperature, humidity, air pressure, etc., the measurement error is large, and because the ultrasonic wavelength is long, the propagation distance is short, so the general ultrasonic range finder The measurement distance is relatively short. , the measurement accuracy is relatively low. However, using the characteristics of ultrasonic wave propagation in a fan plane, its detection range is larger than that of photoelectric rangefinders. It is widely used in safety protection, cable height measurement, obstacle detection and other fields in practical engineering.
