Objective  Aiming at the characteristics of large-scale aquaculture environment covering a wide area and interaction of a variety of water environment monitoring factors, to design a device that can simultaneously monitor five water quality parameters including dissolved oxygen, salinity, pH, ammonia nitrogen and temperature. The device can realize long-distance wireless transmission of water quality data through long-distance wireless communication technology, and dynamically display the monitoring environmental factors on the host computer side visualization platform.

Method  The control core of the data acquisition terminal adopted 16-bit MSP430F149 microcontroller of TI company. The water quality information was collected by various sensors. Ammonia nitrogen collection terminal adopted NHN-202A ammonia nitrogen sensor with test range of 0−10 mg/L. Dissolved oxygen and temperature acquisition terminal adopted RDO-206 sensor with dissolved oxygen range of 0−20 mg/L and temperature range of 0−40 ℃. pH collection terminal adopted PHG-200 sensor with test range of 0−14. Salinity collection terminal adopted DDM-202I/C sensor with test range of 0−0.5%. The server side was built using Linux system and built by the IntelliJ IDEA development tool under JetBrains. The programming language was Java. The online platform used the SpringMVC framework, and the database connection was operated through the HiBernate object-relational mapping framework. The monitoring platform was deployed on the Linux system through Tomcat. The data display interface was realized by calling the visualization library Echarts.

Result  The absolute error of dissolved oxygen content measured by the system was 0.12 mg/L, while those of salinity, pH and temperature were 0.001%, 0.017, and 0.05 ℃, respectively. In the power consumption test of single acquisition device, 5 200 mA battery could continuously supply power to the terminal device for 28.5 h, and the online system was stable.

Conclusion  The combination of LoRa wireless communication technology and the data visualization platform on the host computer side in the device enhances the reliability of the long-distance water quality monitoring, and solves the problems of long-distance transmission of monitoring data in dynamic real-time measurement and display of data synchronization on the host computer platform.