Ultrasonic remote control liquid level control and indication circuit

As shown in the figure, the circuit includes two parts: ultrasonic transmitter and ultrasonic receiver and control circuit. Taking advantage of the fact that ultrasonic waves have large propagation loss in the air, as well as the propagation characteristics in different media such as gas and liquid, the separated emission type ultrasonic technology shown in Figure (a) is used to measure distance, liquid level or material level. This circuit uses this principle to indicate and control the liquid level of large tanks. The signal strength of the ultrasonic wave transmitted to the liquid surface and emitted back from the liquid surface is related to the propagation distance. The signal attenuation is large when the liquid level is low; the signal is strong when the liquid level is high. The ultrasonic transmitter and receiver are placed on the top of the large tank to indicate and control the liquid level.