Design Of Temperature And Humidity Control System Based On Micro-controller

From the industrial revolution to the present, science and technology have made greatprogress, promote the continuous development of human society, and the living standard hasbeen greatly improved.Especially in the last twenty or thirty years, with the wide application ofcomputer, it brings much convenience to people, makes people towards the intelligent direction.But, the development of science and technology will also bring some environmental problems,such as air pollution, water pollution and so on. These problems influence the people’s livesevery moment of every day. In recent years the haze weather also received wide attention, so it isvery important to solve environmental problems, especially improve people’s living environment.As the two important factors of the environment, temperature and humidity is the most basic andeasy to have a actual measurement, and it has important significance to improve people’s comfortand health environment.Atmega16is designed as the core of the thesis, which is a8bit AVR microprocessor withhigh performance and low power consumption. Wireless transmission used, module designadopted, the thesis sets up a system of collecting and changing indoor temperature and humidity.It mainly includes temperature and humidity data acquisition module, wireless data transmissionmodule, data processing module and temperature and humidity control module. Temperatureand humidity data acquisition module uses the digital temperature and humidity sensor DHT11,then the wireless transmission module transmits the data by the wireless transceiver chip nRF905after processing to MCU, MCU can automatic judgment whether to start the control moduleafter analysis the data. DHT11has excellent quality, fast response, strong anti-interference abilityand high performance-price ratio, nRF905has a high Integration, Atmega16has a excellenceperformance, this advantages not only make the system very powerful in function, but also makethe whole design simple. In order to show the changes of temperature and humidity intuitively, italso designs the interface circuit of MCU and PC, Through the level conversion chip MAX232,using RS232interface,it achieve a connection with the PC. This design designs a control moduleaccording to the need of the design of temperature and humidity, making the system more complete. The software design is also very important, so when designing the hardware,software’s flowchart is well designed too, so as to ensure that the system can run perfectly.The thesis designs a temperature and humidity control system in which Atmega16was usedas the core and wireless transceiver chip nRF905was used as the transmission chip. Throughthis system,we can collect and change temperature and humidity conveniently, so as to improveour living conditions. The system has a function of wireless communication which can savespace, and also has good stability and low power consumption. It is suitable for a wide range ofapplications.