Wireless Sensor Networks Based Indoor Environmental Monitoring System

Because of the difficulty of laying line and high cost in conventional environment monitoring system, this thesis presents an indoor environment monitoring system based on WSN for the optimizing and control of central air-conditioning. Firstly, this thesis introduces the wireless sensor network architecture, and choose the hardware platform, operating systems and programming languages in accordance with the requirements of the practical application of the system. Secondly, this thesis proposes a tree-form network topology based embranchment of floor of builds in accordance with the distribution of central air-conditioning in edifice, and designs indoor environment monitoring system of central air-conditioning based on the topology, including system architecture, hardware selection and circuit design. At the part of system software structure, this thesis introduces the blocking programming language nesC, focuses on analysis of the TinyOS operating system kernel, scheduling mechanism, communication model, and a detailed description of the present system of wireless communication process. Thirdly, this thesis also focuses on the specific application of the system in the central air-conditioning, including the control of the total air volume, control of temperature of supply air and adjustment of supply air volume.And then, this thesis makes data collection experiment for the indoor environment monitoring system. At first, disposes the node loaded data acquisition applications arbitrarily in each room, and the node constitutes a wireless sensor network through the self-organizing way. Each node collects environmental information and transmits it to the cluster node, after further analysis and treatment to the base station, and ultimately to the central air-conditioning unit control system which provides control accordance for the precise regulation of air.After repeated experiments, results shows that the system can run long time stability, and reflect the goals of the environmental state of the room accurately, and provides accurate and timely information of the environmental parameters for the central air-conditioning unit control system. Consequently the volume of the central air-conditioning supply in accordance with factual demand is calculated. Therefore, the indoor environment monitoring system is able to achieve both precise control of temperature and humidity in the indoor environment and energy saving.