Abstract:
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.