Design of wireless sensor network node for field information acquisition

Timely and correct getting field information is the foundation of implementation of precision agriculture. Four typical wireless sensor network (WSN) nodes for field information acquisition were analyzed. Necessity of designing small-size and long-life field information acquisition WSN node was proposed. Node hardware structure was presented. The RF communication circuit was designed based on ATmega128L and CC1000. The choice and index parameters of sensor for soil moisture/temperature/conductivity, air moisture/temperature and illuminance were listed. Design of software was described. A priority-based static task scheduling mechanism was realized on the node. SYNC frame of S-MAC was integrated with RTS/CTS frame, and a dynamic scheduling mechanism in the sleeping period was added in the integration. A networked long period sleeping mechanism was completed in the communication protocols. Curve of node system voltage change and curve of handling capacity were given after experimental study. The experiment results demonstrated that the node could handle 6 packets per second and can work 150 days continuously, under the conditions of 20 nodes full-coverage networks and 10 minutes sampling cycle. Therefore, the nodes can meet the demand of field information collecting in precision agriculture.