宽带低频振动能采集器驱动的无线传感节点

Wireless Sensor Node Powered by Broadband Low-Frequency Vibration Energy Harvester

提出一种自供能的无线温湿度传感节点,其主要由振动能采集器、电源管理电路、微控制器、温湿度传感器和无线收发模块构成,无线传感节点由一个带滚珠的低频宽带振动能采集器供电。当加速度的幅值频率分别为9.8 m/s2和18.4 Hz,负载为140 k?时,采集器一根压电梁的输出功率为0.51 m W,半功率带宽为17.8%或3.8 Hz。电源管理电路包括LTC3588-1芯片、LT3009芯片和一个2 200μF的电容,微控制器采用低功耗MSP430F149单片机,无线收发模块采用n RF24L01。实验结果表明,当外界环境振动加速度幅值为1 g,频率从5 Hz增加到18 Hz时,该节点均可正常测量并发送环境的温湿度信息,只是时间间隔由848 s缩短为60.2 s。采集器的宽带低频特征使该无线传感节点可应用于多种环境。

A self-powered wireless sensor node for temperature and humidity measurement was developed. It is mainly composed of a vibration energy harvester, power management circuit, microcontroller, temperaturehumidity sensor and a wireless transmitter. The node is powered by a broadband low-frequency vibration energy harvester with a rolling mass. The measured output power of the piezoelectric bimorph on an 140 k？ resistor is 0.51 m W under base acceleration with the amplitude of 9.8 m/s^2 and frequency of 18.4 Hz, and the half power bandwidth is about 17.8% or 3.8 Hz. The power management circuit mainly consists of LTC3588-1, LT3009 and a 2 200 μF capacitor. The microcontroller and the wireless transmitter are MSP430F149 and n RF24L01, respectively. Experimental results show that, under the base acceleration excitation with a constant amplitude of 1 g, the wireless sensor node works normally when the excitation frequency increases from 5 Hz to 18 Hz, whereas the time interval for the node to measure and send out the temperature and humidity decreases from 848 s to 60.2 s. The broadband and low-frequency properties of the harvester makes this wireless sensor node can be used in many environments.