The Design And Research Based On Embedded Wireless Monitoring System For Air Quality

With the modern high-tech progress, people's living standard has been greatly improved. At the same time, the demands on the environment are more and more strict and the society has been paying attention to environmental issues, especially on air quality of our own environment. At present, developing a low-cost remote monitoring system to suit China's national conditions is an important direction in the development of environmental monitoring. How to obtain useful parameters in the environment is an important part in the environmental air quality monitoring system. Only by obtain the environment parameters, the analysis and the decision-control work can be carried on. Wireless sensor network (WSN) could monitor real-time, detect and gather cooperatively all kinds of information about monitored objects through various integrated sensors. And then it transmits the information to remote control center. WSN can be a rapidly developed, automatic, low power consumption and low cost system. Therefore, the WSN is very suitable for the environmental monitoring system.Wireless sensor network was formed by the combination of sensor, embedded system, computer network and wireless communication technologies. WSN can be widely applied in military, commercial, medical and environmental monitoring fields. This paper will design an embedded environmental air quality monitoring system based on WSN.WSN consists of a large quantity of sensor nodes, each one equivalent to a small embedded system, which consists of data acquisition module, data process module, wireless transceiver modules and power supply module. Every node's power is supplied by tow v-type battery, so their power and calculation ability is very limited. Therefore, this paper makes an assessment and selection on the key chip required for this small-scale embedded system. And adopt ultra-low power consumption MSP430 and CC2420 2.4GHz RF chip to design a low-power system architecture.Traditional wireless routing protocol is not suitable for wireless sensor network, the design of existing routing protocols are based on the specific application environment. In accordance with the environmental requirements of this thesis, the key point for researching is to design a valid routing protocol which can save power and prolong the lifetime effectively.This paper firstly analysis current routing protocols of wireless sensor network, especially focus on the analysis of LEACH routing protocol. Then aiming at the disadvantage that this protocol has high power dissipation and short lifetime. Based on the LEACH routing protocol, we improve the LEACH routing protocol, named the advanced routing protocol LEACH-IMP. In this new protocol, we calculate the optimal number of cluster head, improve cluster head selection algorithm and inter-cluster routing mechanism. LEACH-IMP fully takes into account the residual energy of nodes as a cluster head to redefine the threshold value of T(n); and adopt multi-hop routing for the communication between Sink node and cluster node.Improved routing protocol LEACH-IMP to ensure the optimal number of head clusters and more evenly distributed in the region ,at the same time balance the energy consumption of every node, which greatly extend the life cycle of the network. After simulation testing, the LEACH-IMP algorithm has better optimization of energy characteristics to extend the lifetime of the entire network nearly 60%.