Design And Implementation Of Water Film Instrument System Based On Internet Of Things

As the highway mileage in China continues to increase,the importance of road sensors in the field of traffic safety is also increasing.As an important part of the road sensor system,the water film thickness detector is responsible for monitoring the thickness of the accumulated water,which can feed back the information of the accumulated water at specific location to the weather station in an all-weather,conveniently and quickly way.In order to improve the detection accuracy of road water film thickness and the real-time performance of accumulated water thickness information,this paper designs a high-precision and realtime water film thickness detector with FPGA as the core and 4G wireless technology as the communication mode.This paper mainly conducts specific research on the following aspects:(1)Research on water film ultrasonic thickness measurement technology.In order to determine the reliability of the application of water film thickness measurement technology,the current mainstream water film thickness measurement principle was reviewed and analyzed.The transit time detection method in ultrasonic technology was determined as the theoretical basis of water film thickness measurement,and cooperate with algorithm optimization,temperature compensation and error compensation to propose a feasible scheme of water film thickness detector with resolution of 0.01 mm.(2)Research on system hardware design.First,use the LDO to step down and regulate the voltage and power the system.Design and manufacture a driving circuit and echo signal receiving circuit of a transceiver integrated ultrasonic sensor.The FPGA is used as the main control core,and the temperature feedback is added to correct the propagation speed of the acoustic wave in real time to improve the measurement accuracy and reduce the error.Finally,the data is reported through the 4G module.(3)System software design and data reporting.The drive signal module,echo signal capture module,gating signal module,error compensation optimization module,temperature measurement module and 4G communication upload data module are designed to generate ultrasonic sensor 1MHz.The system comes with a digital tube to display the measurement data for more direct data observation during the development process.The 4G communication module is connected to the Alibaba Cloud Io T platform through standard AT commands and reports when a water film is detected.The average current of the 4G module in the sleep state is 1.8m A,and the average current of the low-power mode for sending data is 3.1m A.The experimental results show that the measurement range of the system is 0mm-46 mm,the accuracy is 0.3mm,and the resolution of the data reported to the cloud platform is0.01 mm.When the system uploads data in real time,the average current is 190 m A,the power is about 1.14 W,and the whole system has high stability,which can be used for water film thickness monitoring in various situations.