Wirless Network Design Base On Zigbee Protocol

Wireless sensor network is consisted of a large number of cheap micro wireless nodes distributed in the monitoring regions, and it is formed a multi-hop and self-organizing network system through wireless communication to perceive with cooperation, collecting and process perceptual object information from areas which the network covering, and send the information to observers. Wireless sensor network, based on the application environment, has characteristics of low-cost, low power consumption and high reliability. The birth of IEEE802.15.4/ZigBee protocol and the rapid development of microelectronic and communication technology provide software and hardware platforms for development of Wireless sensor network. The reliable communication is achieved between two wireless nodes and a four-node star network is formed in this thesis.In this project two parts is included in the hardware of wireless node, one is the main control circuit and the other is RF card circuit. The function of main circuit is control the work of RF card through programming based on IEEE802.15.4/ ZigBee protocol. RF card circuit is combined the antenna circuit and receiving /transmitting circuit. A low-cost MRF24J40 of Microchip Technology Inc is used as RF chip. The key of design a RF card are micro strip antenna and electromagnetic simulation on PCB board. The experimental results shows that the wireless sensor node is met the design goals essentially. Four wireless sensor nodes may communication in the master-slave way and a four nodes star network is achieved.