Development Of Wireless Monitoring System Based On ZigBee Technology In Cold Chain

Intentions:The blood,vaccine,biological preparation and medical products are easily affected by temperature,cold chain equipments must be used to protect these products. Cold chain equipments have to be available in such aspects as blood collection, separation,processing,refrigeration,freezing,cryopreservation for strategic reserve, transport,monitoring temperature,rewarming and transfusion.The cold chain equipments in China,with the storing chest as the basic support unit,are gifted with the characteristic of local diatribution,whose individual temperature monitoring makes itself not behave well in real-time response,data concentration and mobility.So,to meet the requirements of cold chain in China,a wireless monitoring system is developed by wireless sensor network,based on the analysis of such features of cold chain as relative centralization,local distribution and bulk flow.Methods:The wireless monitoring system based on ZigBee technology in cold chain was put forward with the investigation of cold chain logistics in the world as well as the cold chain and blood cold chain equipments in China.ZigBee technology hi-directional wireless communication technology,with the excellences of low power consumption, low cost,high network capacity and high robustness,was used to develop wireless sensor network node and wireless monitoring system composed of ZigBee network and tele-monitoring center.With the system above mentioned,realtime temperature monitoring in cold chain,temperature information concentration,database memory, temperature analysis,information integration in cold chain,and terminal query for product source could be realized.Contents:The works in this paper included the hardware design of wireless network nodes for cold chain monitoring,the software design of ZigBee devices and distance monitoring center,and the design and implement of experiments of validating the system.The main contents are as follows,(1) The MC13213 chips,Freescale's second-generation ZigBee platform,are used to design wireless network nodes for cold chain monitoring.The design of MC13213 module and its RF peripheral circuits are chiefly introduced in the hardware design of control nodes and temperature acquisition nodes.(2) Application layer development for ZigBee coordinator and ZigBee end devices based on IEEE 802.15.4 MAC stack which Freescale BeeKit Tool provided,and the software design of application interface of each device are implemented in Freescale Code Warrior IDE. (3) Cold chain information database is created by SQL Server 2000,and Cold chain monitoring system and client terminal are developed in Delphi 7 IDE.Cold chain monitoring system is regarded as distance monitoring center.The software design of UART interface of ZigBee coordinator are used to build the communication express between ZigBee notwork and distance monitoring center.(4) The experiments are designed to validating reliability and stability of the system allowing for the features of ZigBee technology and cold chain monitoring,and the results of implement are come up for discussion.Achievements:The following achievements were obtained in this paper:(1) The single and simple function of temperature monitoring of blood cold chain equipments were improved and perfected by real-time temperature monitoring and early alarming during the refrigeration and preservation period.(2) The communication ability of ZigBee network was enhanced and the range was expanded by the design of RF power amplifier circuits based on MC13213 chip.(3) Application of ZigBee star network was successfully performed by developing application layer based on IEEE 802.15.4 MAC stack for ZigBee Coordinator and ZigBee end devices,and transplanting it to control node and temperature acquisition nodes.(4) The advantages of low power consumption,low cost and high reliability of the system are validated by the experiments of blood transportation chest wireless monitoring network consisting of ZigBee network nodes and cold chain monitoring system.Conclusion & Prospects:ZigBee star network devotes itself to wireless monitoring of simple environment for blood preservation,and the integration of ZigBee network into tele-monitoring center can be applied to tele-management of monitoring information and terminal query for product source.Improved network communication by RF power-amplifier circuits makes batch management of blood preservation and information integration in cold chain come true.In the future,the investigation is going to make great efforts in the three aspects as follows.Firstly,RF low noise preamplifier circuits will be used to increase the communication distance to improve the adaptability, robustness and extensibility of the system.Secondly,flexible network construction and safe communication mode will be realized through peer-to-peer network and its extended network.Thirdly,completely wireless monitoring will be implemented by seamless connection between ZigBee network and other wireless network.