The Design And Implementation Of Campus Environment Wireless Monitoring System Based On LoRa Technique

In recent years,frequent occurrences of safety accidents such as fires and thefts on campus have not only affected the normal learning of teachers and students,the normal development of campus activities,but also caused a large number of casualties and property losses.Most of these accidents were caused by inadequate monitoring of the campus environment,poor management,and untimely detection,which consequently cause the missing of the best opportunities to take remedial measures and finally lead to disastrous consequences.At present,most of the implementation schemes for the campus environment monitoring are based on RS485 or short-range communication ZigBee.These solutions have the drawbacks of cumbersome wiring,insufficient communication distance,and multi-level routing.Therefore,these have not yet been applied on a large scale.Against the above shortcomings,this thesis has designed and implemented a campus environment wireless monitoring system based on LoRa.This thesis analyzes the needs of the campus environment monitoring and designs system architecture.We complete the hardware and software design of various types of nodes and solve the problem of reducing the power consumption of nodes,improving the wireless coverage and node capacity.Based on this,this thesis builds a campus environment wireless monitoring system and tests function and performance of the system.The details are as follows:(1)This thesis completes hardware design,PCB drawing and circuit debugging of temperature and humidity detection node,smoke alarm node,door and window switch detection node,and leak detection node.Based on the LoRaWAN protocol,we have developed software for various types of nodes.(2)This thesis optimizes power consumption of various nodes and wireless transmission distance.This thesis selects low-power microcontroller and sensor chip for nodes,optimizes circuit design,discards the RF transponder switch chip,and separates the receive and transmit channels.The sleep current of all kinds of LoRa nodes is below lOuA,and the lifetime of disposable lithium batteries with 2000mA·h can reach about 3 years.The outdoor communication distance between the node and the gateway can reach 800 meters in the case of blockage of buildings,and a 10-storey building can be covered indoors.(3)This thesis completes a campus environment monitoring platform combining the LoRa gateway.This platform includes server management software,data display and analysis software,and many functions such as system configuration,abnormal alarm,mobile phone APP,and SMS mail alarm.The system has been commissioned at Entrepreneurship College of CCNU.