Abstract: In view of the current problems of sea buoy dissolved oxygen (DO) sensors such as high power consumption, complex calibration processes, etc., a STM32-based DO monitor with low power consumption and high performance was designed, which realized the automatic calibration of the DO sensor through infrared calibration design. With the design, the DO value can be accurately calculated using the combination of single power data acquisition circuit and multi-channel STM32 ADC. The design makes use of the input capture function of STM32 to decode the infrared remote control signals, realizing the slope calibration of voltage-DO curve, and effectively avoiding the tightness risks of buoys caused by the frequent disassembly due to calibration of oxygen. Power saving mode meets the requirements of low power consumption and can improve the power supply duration of the battery. The RS485 port integrating with the MODBUS protocol can achieve remote communication, and lay a solid foundation for remote monitoring. Experimental results show that the DO acquisition accuracy of the monitor is higher, and monitor can run continuously for 5-6 days under no-light condition. This design can greatly improve the stability and tightness of buoys, and provide great convenience for the working staff with the advantages of low cost, small volume, and easy installation.

Key words: STM32, water quality monitoring, infrared calibration, dissolved oxygen

摘要： 为解决海上浮标溶氧传感器存在功耗大、标定复杂等问题，研究设计了一种基于STM32的低功耗、高性能溶氧监测仪，并针对海上浮标提出红外标定设计，实现溶氧传感器的自动标定。利用单电源数据采集电路结合STM32多通道ADC，精确计算出溶氧值；利用STM32的输入捕获功能解码红外遥控信号，实现电压-溶氧曲线的斜率标定，最大程度避免因溶氧标定而频繁拆卸，造成浮标体内部密封性变差的风险；省电模式满足低功耗的要求，可以提高蓄电池的供电时长；集成MODBUS协议的RS485端口可实现远程通信，为远程监测打下基础。结果表明，监测仪溶氧采集精度较高，能在无光照情况下连续运行5~6 d。该设计可以提高海上浮标的稳定性和密封性，为工作人员提供了极大的便利，具有成本低、体积小、便于安装等优点。

关键词: STM32, 水质监测, 红外标定, 溶氧