基于无线传感网的荔枝园智能节水灌溉双向通信和控制系统

为提高水资源利用率和灌溉智能化管理的需要,设计了以无线传感器网络技术为核心的荔枝园节水灌溉控制系统,该系统的无线通信模块选择CC2530模块,传感器模块包括空气温湿度传感器DHT22,光照强度传感器GY-30,土壤水分含量传感器TDR-3以及一些外围电路,精确采集荔枝园温度、湿度、光照度和土壤含水率等多项环境信息,通过无线传感器网络、通用分组无线服务技术(General Packet Radio Service,GPRS)和互联网进行数据的传输,保证了传输的实时性和远程性,实现了对荔枝园环境的实时监控;同时,远程服务器和网站上都对荔枝园的土壤含水率的阈值进行了设定,当土壤含水率的值超过了阈值,服务器或者网站就会自动发送相关命令对相应的电磁阀进行控制,实现双向控制。分析、测试了系统的功耗和通信距离,在空旷地带,节点的双向有效通信距离达1 205 m,在荔枝园中双向有效通信距离达81.5 m。在传感器节点系统工作周期为30 min情况下,根据试验结果估算出,两节额定容量为3 000 m A·h的3.7 V锂电池串联可使传感器节点持续工作时间最大为500 d,可使电磁阀控制节点工作5 a以上。试验结果表明,该系统运行稳定,网络平均丢包率为3.87%,能够准确监测荔枝园信息采集和控制电磁阀工作,实现和控制荔枝园智能节水灌溉双向通信。

Bidirectional communication and control system of intelligent water-saving irrigation in litchi orchard based on wireless sensor network

In order to improve the utilization of water resources and satisfy the needs of intelligent irrigation management, an intelligent irrigation system combined with wireless sensor network technology as the core in litchi orchard was designed.The system used CC2530 as wireless communication module, combined with DHT22 air temperature and humidity sensors, GY-30 light intensity sensor, TDR-3 soil moisture sensor and peripheral circuit as a sensor module to collect a number of environmental information and data such as temperature humidity, light and soil moisture content.To achieve a real-time monitoring of litchi orchard environment, it ensured the transmission of real-time and remoted via wireless sensor networks, GPRS and the Internet transmission.In the mean time, litchi orchard soil moisture water content threshold had been set on remote servers and websites, when the value of the soil moisture content exceeds the threshold, the servers or websites would automatically send the relevant commands to control the corresponding solenoid valve to realize two-way control.The maximum bidirectional effective communication distance of the designed nodes reached 1 205 m in open field and 81.5m in litchi orchard.With a working cycle of 30 min, it could be estimated that two series lithium batteries with a rated capacity of 3 000 mA·h allows sensor nodes operating time up to 500 days and the solenoid valve control node can work more than 5 years.Experimental results showed that the system is stable with the average network packet loss rate of 3.87%, which can monitor the collection of information and control the solenoid valves accurately to achieve a bidirectional communication and control system of intelligent water-saving irrigation in litchi orchard.