Wireless Sensor Networks Based On Zigbee Technology

Wireless Sensor Network(WSN) is a short-range wirless network, which consistes of densly deployed large number of sensor nodes with different specifications and functions. All sensor nodes have the abilities of apperceiving, computing and communication, which form a network through ad-hoc mode. Its purpose is cooperation and sense, collection and processing of perceived target information in the region of network coverage, and then sends it to observers. Sensors, targets and observer of the three elements constitute a senor network.ZigBee is the wireless communications technology nearly two years before stereotypes. The IEEE 802.15.4-2003 standard defines the lower two layers: the physical (PHY) layer and the medium access control (MAC) sub-layer. The ZigBee Alliance builds on this foundation by providing the network (NWK) layer and application layer. In the short-distance and low-rate wireless communication, Bluetooth and wireless LAN has incomparable advantages. ZigBee technology has a broad market in the domestic system control, building automation, industrial monitoring field.ZigBee has good market prospects in establishing underground wireless real-time environmental monitoring system, but still exists many problems that need to be resolved, including electricity, energy conservation, the formation of self-organizing network and wireless node positioning technology.This paper firstly introduces the theoretical knowledge of ZigBee networks and wireless sensor networks , explains the MAC layer and Physical Layer defined by IEEE 802.15.4 std, and on this basis the underground. network solutions of monitor system is given; Secondly, we design a wireless data transmission module working at 2.4Ghz frequency; Finally, in software design, the realization of a network algorithm is introduced detailedly and system software charts are mainly given.Our experiments show that our proposed solution achieves the design requirement with satisfying flexibility and expansibility. Consequently, it acts as a platform of wireless monitor system and supplies a new hardware design approach for wireless sensor networks.