| "Smog" from a fresh word to now have become a common word for people,people begin to pay attention to air pollution,the "invisible killer”.Because now the air is full of a large number of waste gas pollutants produced by industrial production and daily life in addition to the oxygen and hydrogen needed by the human body.With the development of social modernization,the focus of people’s activities has shifted from outdoor to indoor.The quality of indoor air affects people’s health.Therefore,this paper designs an indoor air quality monitoring system to achieve real-time monitoring of indoor air quality.Considering the requirements of low energy consumption,low cost,and unified monitoring of multiple indoor spaces,this paper decides to build an air quality monitoring system based on the ZigBee wireless sensor network to realize real-time monitoring and data visualization of indoor air quality.The system is divided into two parts: lower computer and upper computer.The lower computer is responsible for data collection and data packaging and forwarding,and the upper computer is responsible for data storage,processing,and visual display.The lower computer part is composed of ZigBee terminal and ZigBee coordinator to form a wireless sensor network,CC2530 wireless module is used in both terminal and coordinator nodes.ZigBee terminal is connected to the DHT11 temperature and humidity sensor,CJ-01-SH22 electro-optical formaldehyde sensor,CP2Y1014 AU dust sensor,and MQ-7 carbon monoxide sensor,use those sensors monitor the indoor air pollutant value in real-time.The ZigBee coordinator collects monitoring data from multiple ZigBee terminals and transmits the monitoring data to the server after packaging.Based on the Z-Stack protocol stack designed by Texas Instruments,designed the data acquisition function of the terminal and the network data forwarding function between terminal and coordinator nodes.The upper computer system is divided into two parts,the first part is the design and implementation of the system server.The server implements the communication with a lower computer,stores the data collected by the lower computer,implements the data preprocessing,air quality evaluation methods,storage process,and the evaluation results,and provides data request and data storage service for the mobile terminal by a socket.Next is the mobile client design and implementation.Android technology is used to design a mobile client,which will collect the pollutant value and data pre-processing to obtain the pollutant pollution level,and the evaluation results will be displayed on the user’s mobile phone through the visual effect,and the early warning can be made according to the pollution level so that users can master the indoor air situation anytime and anywhere.To better show the current indoor air quality to users,based on the realization of the lower computer system,this system uses the concept of relative membership degree in fuzzy mathematics to preprocess the original data of the sensor and obtains the pollution degree of pollutants through the monitoring data of pollutants.Through calculating the Euclidean distance between the monitored samples and the standard values of air quality,the total indoor quality assessment of all pollutants in the samples is given.Finally,through the overall functional test of the system,proved the system’s functional design is meet the needs of users,confirmed the data acquisition module of the lower computer runs stably,the data transmission between the various parts is normal,and the evaluation results of the air quality evaluation method are reasonable.The user can use the mobile client to conveniently and quickly monitor the indoor air quality in real-time. |
