水下磁感应无线通信模块设计

Design of Underwater Magnetic Induction Wireless Communication Module

摘要:

为了解决海洋观测系统中传感器节点与主机之间的无缆信息传输问题,设计了一种基于磁场耦合的低功耗水下半双工无线通信模块。通过线圈之间的电磁感应进行信息传输,采用二进制频移键控(Binary Frequency Shift Keying,BFSK)调制方式对基带信号进行调制。选用超低功耗单片机MSP430F5338作为主控单元。通过内部定时器的输出模块产生调制载波,在外部中断中进行频率切换,实现信号调制；采用专用解调芯片XR2211实现信号解调。模块由通信总线上的信号唤醒,设计了一种通过软件检测载波信号的方法,降低误触发概率。实验结果表明,模块在水下间隔2米时,通信成功率达到100%。该模块实现方案简单,成本和功耗较低,满足海洋观测系统中的应用需求。

Abstract:

In order to solve the problem of cableless information transmission between the sensor node and the host in the ocean observation system, a low-power underwater half-duplex wireless communication module based on magnetic field coupling is designed. Information is transmitted by electromagnetic induction between coils, and the baseband signal is modulated using Binary Frequency Shift Keying (2FSK) modulation. Ultra-low power microcontroller MSP430F5338 is the main control unit. The modulation carrier is generated through the output module of the internal timer, and change the frequency in the external interruption to realize signal modulation; the special demodulation chip XR2211 is used for signal demodulation. The module is woken up by the signal on the communication bus, a method of carrier signal detection through software is designed to reduce false trigger probability. The experimental results show that the communication success rate reaches 100% when the module is 2 meters apart underwater. The implementation of the node is simple, and the cost and power consumption are low. This module meets the application requirements in the ocean observation system due to the simple design, low cost and low power consumption.