Research And Design Of Water Quality Monitoring System Based On LoRa Networking

With the rapid development of my country’s economy,industry,human life,agriculture,etc.all cause pollution to water bodies,and the prevention and control of water pollution is inseparable from the development of water quality monitoring technology.This paper studies and designs a water quality monitoring system based on Internet of Things technology,cloud technology,sensor technology and web development technology.The main work of this paper is as follows:(1)Three different system schemes are designed,and the design scheme suitable for this subject is selected through demonstration and comparison.The terminal node circuit and the receiving node circuit are designed,and a high-performance LoRa gateway device is selected.The terminal node circuit is composed of various sensor modules,microcontroller modules,and LoRa and GSM communication modules,while the receiving node circuit is composed of a microcontroller module and a LoRa communication module.(2)Due to the problems of low data transmission efficiency and unstable transmission in the process of LoRa networking,an improved intelligent water droplet algorithm is proposed to optimize the networking.By improving the update method of soil content,the selection method of nodes,The algorithm is improved in three ways based on the transition probability of water droplets,and the steps of the improved intelligent water droplet algorithm are given,and the algorithm is simulated,focusing on verifying the network throughput and transmission delay of the algorithm.(3)The program of terminal,data communication and computer terminal is designed.The terminal program mainly realizes the collection of water quality data and the display function of the lower computer.The water quality data information collected by all terminal nodes will be transmitted to the gateway device through LoRa,and the gateway will send the data to the cloud server through the 4G frequency network after receiving the data..The computer terminal consists of four parts: the upper computer,the application server,the server database and the water quality monitoring website.The receiving node is connected to the computer through the serial port to realize the visual display of the water quality data of the host computer,the setting of water quality parameter thresholds,the threshold alarm,the data storage and the historical data query and other functions.Based on Alibaba Cloud,an application server was designed,and a water quality monitoring website based on MVC mode B/S structure was built based on the server,and the function and program design of the website were completed.Real-time water quality data and historical data;users can access the website through a computer or mobile phone to check the water quality of the three rivers at any time,reflecting the practical applicability of this topic.A MySQL database is created in the server to store the water quality data information collected by all terminal nodes,as well as website usernames and passwords,equipment information,river and lake information,parameter threshold information,and feedback and processing information for pollution problems.(4)Since there are operational errors or interferences such as electromagnetic waves and electromagnetic fields in the water quality data collection process,the accuracy of the data in this system will be affected.Therefore,a data fusion algorithm is proposed.First,the data is preprocessed,and abnormal water quality is eliminated by Grobes.Then,based on batch estimation theory,data fusion is carried out to improve the validity and accuracy of water quality data.(5)Due to the interference such as noise in the water quality monitoring environment,the Kalman filter algorithm is used to denoise and optimize the data such as the temperature and PH value of the lake water in this system,and the initial state value,the initial value of the covariance,and the noise co-ordination during the system work process are de-noised and optimized.The variance,as well as the observed and measured noise covariance,are set to make the filtering algorithm perform better and converge faster.(6)The terminal nodes and gateways are placed in a star-structured network to test the communication distance of LoRa.Six terminal nodes with different distances send a total of 1500 data packets to the gateway at the same time.The test results show that the system can achieve at least 2000 m 0% packet loss rate within 3000 m,only 2.67% packet loss rate within 3000 m,and set up a system environment in the laboratory to test the hardware,software and overall functions of the system.The test results meet the requirements of this design,and the system has application value.