Designing Of Humidity And Temperature Measuring System Based On WSN

Born on the end of20th century, wireless sensor network (WSN), with its charactersof lower consumption and cost, which distributes nodes having capability of sensing andcommunicating randomly in specified region to form self-organization network havingredundancy data link to measure signal on nodes, has become another technology tocompletely change people’s way of life afterwards the Internet technology. ZigBeetechnology is a typical application of WSN. Inheriting IEEE802.154standard andextending network layer and application layer, ZigBee protocol runs on multi frequencyband such as868MHz,915MHz and2.4GHz, and is the mainstream solution for WSN.This paper summarizes origin of WSN and development history of ZigBee technology,which is important branch of WSN, and studies PHY layer, MAC layer of IEEE802.15.2wireless communication protocol and NWK layer, APP layer of ZigBee protocol in deeply,and then, researches function of each model in all layers.After sufficient analysis on theory, this paper studies architecture and implement ofZ-Stack which is powered by TI, and discusses resource management mechanism inZ-Stack, then expounding mechanism of the embedded OS (OSAL) about task schedulingand method of user programming on application layer with that mechanism, after whichmakes cutting, transplanting and configuration on Z-Stack and adds driver for device onnode. Using CC2430as MCU of nodes in network, which carries SHT11humidity andtemperature sensor, this paper builds a humidity and temperature measuring system basedon WSN, and develops interface of upper computer by LabVIEW developing platform tohandle the system and display data from lower computer.To examine performance of the system, this paper makes comprehensive test for thesystem on data colleting, function of the upper computer program, the capability of routingself-healing, and analyzes transmission performance of high-power ZigBee block used bythis system, then contrasting the transmission performance with that of common ZigBeeblock. In addition, analyzes expansibility of the system. Experiment and expansibility analysis shows that the system achieving excepted function, with the capability of handledby upper computer program, has an excellent stability, anti-interference and expansibility.