Design Of Wireless Sensor Network Node For Environmental Water Quality On-line Monitoring

Water environment monitoring is the foundation of water resource conservation and management. A wide range and real-time water quality monitoring can accurately represent the regional water quality conditions. At present, water quality information is mainly obtained through the construction of fixed monitoring sites in China. However, the operation and maintenance costs are high, and can only obtain the section water quality conditions. This dissertation studies on-line monitoring wireless sensor network for water environment. This wireless sensor network can realize large range, real-time water quality monitoring, and quickly and accurately obtain the water quality data. The network consists of a sink node and several child nodes. Child nodes transmit data to sink node through wireless network. The sink node transmits the data gathered from child nodes to the remote control center using GPRS communication module for processing and analysis.The main work of this dissertation is as follows:1. The hardware design and implementation of wireless sensor network node for water environment on-line monitoring.According to the system structure and functions, we selected the STM32 microcontroller as the hardware development platform. The sensor signal acquisition module is isolated from the control system by using the DC-DC switch power modules and optocoupler to prevent the module from noise interference. This system includes the RS-485 bus, CC1101 wireless communication module, GPRS communication module and GPS module, and equips with the Human Machine Interface (HMI).2. The software design and implementation of wireless sensor network node for water environment on-line monitoring.Based on embedded real-time operating systemμC/OS-II development platform, the hardware driver was developed, and the system missions are designed to achieve the function of parameter detection, data transmission and human-machine interaction.3. The design and implementation of wireless sensor network communication protocol.The performances of wireless sensor network for water environment monitoring are addressed, and the characteristics of various network topologies are analyzed. We propose a wireless sensor network protocol based on CC1101 communication module. The protocol is divided into physical layer, data link layer, network transmission layer and the application layer. The message formats are defined. LBT strategy and ARQ protocol are adopted to achieve reliable data transmission. The network transmission layer realized the routing and data forwarding, and the self-organization function is implemented by route discovery.