Development of wireless sensor network of field information based on ZigBee and PDA

In order to achieve real-time acquisition, processing and visualization for field information, and shorten the time difference between data acquisition and processing, a wireless sensor network based on ZigBee and PDA was developed. The system consisted of a PDA with a ZigBee coordinator and router nodes with sensors. Via the wireless sensors network, the field information could be dynamically accessed in real time by PDA and the power supply for sensors could be controlled to save power consumption. Here the field information refers to soil moisture, soil temperature, soil electrical conductivity, air temperature and humidity. Soil temperature sensor and air temperature and humidity sensor were digital sensors, while soil moisture sensor and soil electrical conductivity sensor were analog sensors. Node communication test for different distances showed that under normal operating conditions, the packet loss rate of 40 m as only 0.092, met the requirements. In the hop test, the information could be sent from the farthest node to PDA through the self-organizing network accurately. It demonstrates that the network works stably.