Design And Realization Of Digital Ultrasonic Liquid Level Meter

As a new method of non-contact measurement,ultrasonic distance measurement has good adaptability to smoke,poisonous and harmful gas,dark,wet and other harsh working conditions,also has its high performance,low price,simple operation and other characteristics,so ultrasonic ranging technology is widely used in many fields,such as vehicle assistant system in safety driving,liquid level and material level detection system in the industrial applications,robot positioning system and underwater acoustic engineering.Therefore,it is of great practical significance to study the theory and algorithm of ultrasonic distance measurement.In recent years,with the development of electronic technology,ultrasonic distance measurement has more strict requirement in the precision,range and anti-interference performance.The traditional ultrasonic distance measurement system is a simple threshold detection method,however,in complex applications,especially in complex industrial applications,the whole system is obviously inadequate.To slove this problem,this paper introduces the cross-correlation algorithm to increase the anti-interference performance of the whole system.Compared with the traditional threshold detection method,ultrasonic distance measurement also has the obvious difference in the measuring range and accuracy.In this paper,a large range of distance measurement method based on STM32 processor is proposed.The hardware circuit of the system is mainly composed of ultrasonic emission circuit,echo receiving and processing circuit,temperature compensation circuit,LCD circuit and communication circuit.Due to the attenuation characteristic of ultrasonic wave in the air medium,the timing gain compensation circuit(TGC)is added in the echo receiving and processing circuit,which makes the echo signal more stable.In the software design of the system,the cross-correlation algorithm is applied to the ranging algorithm sucessfully,and achieved good results.In addition,the temperature compensation circuit is added to reduce the influence of temperature on the velocity of ultrasonic wave propagation velocity.