| Timely and accurate grasp of paddy environmental system information, has important guiding significance for
scientific regulation of the growth of rice quality. Monitoring the environmental information including paddy soil moisture, air
temperature and humidity etc, is the premise of precise demand irrigation, demand fertilizing and demand spraying. To solve
these problems, a WSN gateway based on directional antenna applied in paddy field environmental monitoring was designed,
and it had the characteristics of automatic alarm and ensured data integrated. The gateway design included hardware design
and software design. A MSP430F149 was used as the gateway core, a nRF905 RF chip was used as peripherals for node
communication. Soil moisture sensor nodes used TDR-3 and air temperature and humidity sensor used DHT22 for paddy
environmental monitoring in real-time. The GPRS module MC55 was used as the communication module, which achieved the
transmission of environmental information and remote monitoring capabilities. In the hardware platform, hardware drivers and
communication protocols, exception message alarm program and time synchronization protocol were written. The
communication distance, power and storage rate of the WSN node were tested, the usefulness of the gateway field was
studied. The results showed that the gateway node communication distance could be up to 331.18 m, the gateway could work
32 days continuously without solar charging, and maximum storage rate was 849.7 kbps. The networking test results showed
that the network packet loss rate was 0.686%, outside the network packet loss rate was 0.712%, sensor node could collect
data steadily, it could meet the requirements of information acquisition in paddy field environmental monitoring. |
