Design And Implementation Of Indoor Air Quality Monitoring System For Academic Building Based On IoT Technique

In recent years,the scale of education in China has been expanding.On the one hand,the number of students is increasing year by year.On the other hand,a large number of new teaching buildings are put into use.In the process of teaching building construction,because of the use of a large number of building materials,the installation of teaching equipment and other factors,the indoor air quality of new teaching building often fails to meet the standard.In the use of teaching buildings,there is also a general lack of toilet odor detection,carbon dioxide concentration measurement in the classroom,household harmful gas emission concentration measurement,etc.If the air pollution can not be found and controlled in time,it will have a serious impact on the physical and mental health of teachers and students.At present,the main problems include:first,there is no targeted air quality testing equipment installed in the teaching building;second,there is partial gas testing installed,but it is not comprehensive and lacks overall evaluation.In view of the above problems,this thesis designs and implements the air quality monitoring system of teaching building based on Internet of things technology.This thesis analyzes the actual needs of indoor air quality monitoring in the teaching building scene,designs the system architecture,completes the hardware and software design of two types of air quality monitoring nodes,builds the air quality monitoring system of the teaching building,and carries out the system performance test and system function test.The main contents of this thesis are as follows:(1)Based on the comparison of a number of national existing indoor air quality standards and the common air quality evaluation system at home and abroad,an air quality standard suitable for the reference of the system is proposed,which is used to judge whether the indicators collected by the system are up to the standard and evaluate the overall situation of indoor air quality.(2)By analyzing the characteristics of the indoor scene of the teaching building and the types and sources of the polluted gases,the formaldehyde,carbon dioxide and particulate matter are determined as the routine indoor air quality monitoring parameters,the toilet scene is taken as the supplement of the routine indoor scene,and the ammonia and hydrogen sulfide are determined as the air quality monitoring parameters of the hygiene room.Completed the hardware design,PCB drawing and simulation,circuit debugging and other work of routine indoor air quality monitoring node and toilet air quality monitoring node in the teaching building.Based on LoRa technology and LoRaWAN protocol,two kinds of embedded software are designed.Both types of nodes have wireless communication and networking functions,and the measurement sensitivity and measurement range meet the design requirements.(3)Combined with Lora gateway,a test system is built,which has the functions of users management,data display,exception prompt and so on.For the data collected by the system,PostgreSQL database is used for management,and web display software and mobile app are used for list display of data.On this basis,the system tests are completed.The system has been installed on the second floor of No.9 academic building of Central China Normal University.The system operates normally and functions well.