基于低功耗传输方法的设施花卉环境监测系统

为了降低现有设施环境监测系统中传感节点的能耗,延长无线传感网络的生存周期,该文提出了节点动态组包主动传输和多种环境变量加权控制传输2种低功耗机制,减少了大量重复冗余数据的传输,并实现了基于Zigbee的设施花卉环境监测及其低功耗传输系统。节点以CC2430芯片为核心,并根据影响花卉生长的环境参数,同时装载SHT10温湿度传感器、BH1750FVI光照传感器以及COZIR二氧化碳传感器,因此节点可同时采集传输多种环境参数,降低了硬件成本。在南农大园艺试验基地进行组网测试,试验结果表明,系统比传统周期传输节点(周期1min)的能耗减少85.97%,测量精度在98.5%以上,网络平均丢包率为0.84%,满足了对设施花卉环境的有效监测及低功耗传输的要求。

Environment monitoring system for flowers in greenhouse using low-power transmission

The node is based on the CC2430 chip as the core, and in accordance with the environmental parameters which affect the growth of flowers, it is loaded with the SHT10 temperature and humidity sensor, BH1750FVI light sensor, and COZIR carbon dioxide sensor, so nodes can collect and transmit a variety of environmental parameters at the same time, which reduces the cost of hardware. Status indication LEDs are used to display the node in the various states. A gain antenna is used to enhance signals and increase the communication distance. The power module is 3V lithium battery. The wireless sensor network is a multi-hop and self-organizing wireless network, the node is battery-powered, and the power of battery is limited, the node will fail when its battery runs out of power. In order to reduce the energy consumption of the sensor nodes in the monitoring systems of the existing facilities environment, and to extend the lifetime of wireless sensor networks, this paper proposes two low-power consumption mechanisms where the node transmits the package actively and dynamically and a variety of environmental variables transmit depending on the weight, and reduces the large number of duplicate and redundant data transmission. This, in turn, reduces the energy consumption effectively. A dynamic group package active transport mechanism refers to the idea that if the change of one of environmental variables exceeds a preset threshold, then it is added to the environmental variable measured value to the transmitted frame payload. Traverse all sensors, the measured value of the environmental variables are added to frame payload dynamically which will be transmitted later. Weighted environment variable control transmission mechanism refers that if the total change of the weighted environment variable larger than the default of the total change in value, the node will send all the measured values of the environment variables. The combined effect of the environmental variable can have influence on facilities flower. The system will establish a network at first and start to collect environmental variables, then it will execute environment variable weighted control transmission algorithm. If changes in the weighted value of the environmental variable are greater than the total change in the default value, it will transmit all the measured values of the environment variables. Otherwise, it will execute dynamic group package active transmission algorithm, the change of environment variables, which exceeds a preset threshold, will be joined send frame payload. Networking test in horticulture test base in the Nanjing Agriculture University, and deploy cycle transmission nodes and low-power transmission node in the greenhouse at the same time to compare each other. the test results show that this system reduce the 85.97% energy consumption than traditional cycle (cycle is 1 minute) node. and measurement accuracy is more than 98.5% which compared with the standard sensors. The network average packet loss rate is 0.84%, which far below packet loss rate of the cycle of transmission that is 2.7%. The system has higher measurement accuracy, strong network stability and the low-power effect of the node is obvious. Therefore, this system satisfies the requirements of facilities flower environment monitoring and low-power transmission.