Design Of Temperature Data Acquisition And Monitoring System Based On ZigBee Technology

In recent years, with the rapid development of embedded technology, communication technology and network technology, wireless communication network technology has more and more influence on daily manufacture and life of people. Wireless network technology is low cost, flexible in net building and no need for complicated wiring, and these features have created favorable conditions for wireless network technology of wide application. Existing short-range wireless communication network technology mainly include: infrared, Bluetooth technology, WiFi technology and ZigBee technology, etc. ZigBee technology as a new wireless communication technology, has the incomparable advantage in low power consumption, low cost, low complexity and low transmission rate compared to several other short-range wireless communication technology.Especially the conbination of ZigBee technology and sensor technology can set up ZigBee wireless sensor networks, which realizes multi point communications. Wireless sensor networks composed by the large number of sensor nodes, deployed in the monitoring area. By way of wireless communication to form a multi-hop network, each sensor node can achieve information collection, data processing and wireless communications and other functions. Currently, wireless sensor networks are mainly used in industrial control, building automation, environmental monitoring, surveillance and other areas of modern agriculture. This paper applies the ZigBee technology to monitor the temperature data acquisition system, in brief, the terminal nodes collect temperature data to the coordinator with the wireless communication transmission, and then transmit the data through the serial port to PC, so that to achieve the monitoring function of the temperature data acquisition.In this paper, a hardware platform was built for data transmission based on the in-depth study of the function structure and work principle of MSP430 and CC2420.The main parts of the hardware are data acquisition module, wireless communication module, the microprocessor module and power module. According to the design requirement of low power consumption, this paper applies the MSP430 F1611as a network terminal node and network coordinator of the MCU. It has the advantages of low power consumption, powerful data processing capability, abundant on-chip resources and high operation speed which can meet the design requirement. Low-power radio frequency chip CC2420 in line with IEEE802.15.4 standard was selected in the wireless communication module.It has the support of IEEE802.15.4 protocol, ultra-low current consumption, and high-speed data transfer rates and many other advantages. Its main chip communicates radio frequency chip CC2420 through the SPI interface.Selecting Digital Temperature Sensor DS18B20 as the data acquisition module completes data acquisition function through microprocessor?s controlling.Developer is convenient to adjust and modify the program according to different states of light and the node's working status.The software development environment of the paper is IAR Embedded Workbench. The generality and requirements of development should be taken into account in node design. The paper transplants TI's Z-Stack protocol stack. It completes application development based on the modification of Z-Stack protocol stack. As the Z-Stack protocol stack using the event wheel to follow the mechanism,this paper triggers the task processing procedure through the pressed key. This paper in view of network node design's application program function as follows: after the node is powered, in the first place is to complete the initialization of the relevant components. After the initialization is completed, enter OSAL operating system. Once entering the OSAL operating system,it will be initiating task dispatch mechanism. Operating system will query the task list continuously, when key events or timer-to-time events occur, it will wake up CPU, and complete forming corresponding networks, joining the network, the temperature data acquisition or data transmission tasks. If there is no ready status in the list when the task is completed, the node's CPU continues to sleep in order to ensure low power consumption of nodes.After testing,each module of system works well, realizes the system network and data communications,and obtains each node of the temperature timely and accurately, and meets its expected function.This paper introduces a solution of wireless temperature acquisition system. The hardware and software of the system have been designed. This paper has reference value for the application of ZigBee technology.