Research And Implementation Of Node And Communication For Greenhouse Wsn Based On Simpliciti Protocol

In order to provide the best environment suitable for crop growth, effectively achieving increased crop yields, improved quality and enhanced economic efficiency, modern control technology and microelectronic technology is the trend of intelligent greenhouse.Nowdays, cable communication based on fieldbus is adopted widely in monitoring and controlling system for greenhouses, this method has several disadvantages such as aging wire and complex lines, which lead to difficult deployment of monitoring system and hard maintenance. Using WSN technology to achieve wireless-network monitor for greenhouse has great significance to improve production level of greenhouse.This paper makes a comparison of serveral short-range communication technology,and then select SimpliciTI,which has advantages of low cost, low power, flexible use, and short development cycle. SimpliciTI network protocol was transplanted into hardware platform of MSP430and STM32,in order to achieve self-organization network and data transmission wirelessly. Gateway node use real-time operating system of RTThread, which has the TCP/IP protocol of LwIP, to achieve communication in ethernet.With SimpliciTI protocol,gateway node transformate protocol between wireless network and ethernet.Greenhouse WSN monitoring system was developed based on SimpliciTI network protocol,the system node’s hardware architecture is MCU combined with radio frequency chip.According to the idea of modular design,wireless communication module that can be used in all node is designed.According to the characteristics of greenhouse environment, Illumination sensor, temperature and humidity sensor, carbon dioxide sensor was selected and designed modulely. There are sensor node, control node, image node, relay node and gateway node in system.the power-control circuit of sensor node was designed,so when the node is sleeping,the power of sensor can be put down,in order to reduce power of node. Storage space of image node was expanded,in order to compress image with JPEG algorithm.The micro-controller of image node and gateway node is compatible, and gateway node was expanded with ethernet controller of ENC28J60to access external network.The result of test indicate that image node has great performance of compressing image, the compression ratio is8.5:1, and almost there is no difference between image of compression and original image. Sensor nodes were deployed in greenhouse,relay nodes also were deployed,they form a wireless network of tree topology. Sensor nodes acquire information of temperature, humidity, Illumination, carbon dioxide in greenhouse, and then send information to gateway node, finally the information is transmitted from gateway node to local control center.The system runs stably and reliably, can satisfy the design requirement for greenhouse monitoring. System provide a new solution to achieve a wireless-network greenhouse.