The Research And Application Of Wireless Sensor Network In Environmental Monitoring System

Wireless Sensor Network (WSN) monitor information of environment or other objects through kinds of sensor terminal, and process the information through embedded system and pass on the information to user terminal through self-organized wireless communication network in a way of multi-hop router. Zigbee protocol is a wireless network protocol, which is designed for low-speed sensor and controlled network especially. Zigbee protocol suit for WSN, for it has features as low- consumption, low-cost, great network capacity, strong self-treatment ability, and simple protocol and so on.Contra posed the problem of hard-routing, high-cost of building and maintaining existing in the traditional Environmental Monitoring, a new method of applying WSN based on Zigbee wireless communication technology to environmental monitoring is proposed. Compared to the traditional system, there are lots of characteristics like low cost, low influence, maintain and control easily, no routing, arrange monitor nodes lots of number and so on. In this paper, a method of adopting star network to establish environmental monitoring system is given. This system is designed and realized by using CC2420 Zigbee module and PIC18F4620 MCU taking monitoring the temperature information of environment as example.By the way, a new router protocol based on AODV protocol is given in this paper. AODV protocol is a ripe router protocol that is implicated in traditional wireless network. A method is given to modify the original AODV protocol and make it suit for WSN. The simulation results prove the new mechanism works well. This method provides a new development aspect for WSN router protocol research.This paper is divided into 5 chapters; each chapter is introduced as follows:Chapter 1 first introduces the characteristics, key technology of WSN, then, gives out the application foreground of WSN in environmental monitoring, which both prove the advantage and value of this project.Chapter 2 introduces the Zigbee technology, its protocol and its topology structure.Chapter 3 proposes a fundament of environmental monitoring based on WSN, and introduces a new router protocol based on AODV protocol. The detailed process on modifying, design, simulation of the new router protocol is given.Chapter 4 designs a wireless sensor network system, which is used to monitor the variation of environmental temperature. It concludes 2 parts. In the first place, the hardware design of this system is given including the choice and design of important electronic components. In the second place, the software design of this system, especially the realization of Zigbee protocol stack is described.The last chapter is a conclusion of my work, and also proposes future expectation.