Research And Realization On The Wireless Frost Sensor Node

It’s necessary to detect the existence of frost and frost affected area on time in order to reduce the losses resulted from frost disaster. However the frost sensors existing now are all applied on the heat-exchanger surface of refrigerator. No matter what the resonator type is, photoelectric, piezoelectric or capacitor, the frost sensors’ working theory are all based on frost layer, and the detection precision is very low when frost layer is thin, which make them can’t be used in the dust environment such as agriculture. So it is necessary to make a research on frost sensor which can be used on agriculture and don’t base on frost layer. Considering the wide range of detecting area, it has more significant meanings if the data of frost sensor can be remoter monitored by wireless communication.This paper give two proposals, either work on the theory that there will be heatexchange or it needs some conditions when begin frost process. The first proposal detect frost based on latent heat releasing phenomenon, while being verified that it can’t be implemented by experiment and theoretical analysis because of the complexity of the heat conduction and its high demand on detection conditions. Then the second proposal working on the detection of environment temperature and moisture, for the frost can’t be generated if environment don’t satisfy certain temperature and moisture conditions. This method is very simple and has low requirements on temperature or moisture sensors. Above all, we adopt the second one as main research content.The main jobs of this paper include four parts: first, complete hardware design of wireless frost sensor nodes and realize the detection algorithm by software. Second, build a PID temperature control experiment platform to simulate the frost environment and to verify the accuracy of frost detection algorithm, and provides Kingview real-time monitoring interface besides. Third, finish coding wireless frost sensor node based on Zig Bee2007 / PRO protocol Z-Stack, develop a wireless network monitoring interface based on VC++ 6.0 MFC for detecting sensor nodes wireless communication function. Last, test the frost detection accuracy and the wireless communication function of wireless frost sensor nodes, give some analysis according to the experiment phenomenon such as the dew don’t freeze in sub-zero, the frost always generate after dew frozen.Verified by experiment, the wireless frost sensors have good performance on frost detection and can communicate with each other through Zig Bee technology. Especially if being given further research in the future the wireless function makes them more practical in agriculture area.