基于STM32低功耗磁弹性传感器检测系统的设计

Design of a Low-power-consuming Magnetoelastic Sensor Detecting System Based on STM32

具有无线、无源、低成本、高灵敏度等特点的磁弹性传感器已在各个领域得到了广泛的应用研究,然而现有的检测装置通常体积较庞大、功耗高、便携性差,限制了该类传感器的应用范围。对此,本文设计了一套基于STM32的便携式、低功耗共振型磁弹性传感器检测系统。系统以扫频法为检测基础,以STM32为控制核心,永磁铁作为偏置磁场激励,集成交流激励信号单元、信号检测与采集单元,并利用SD卡存储测量数据,采用锂电池供电。实验结果表明:检测系统可使磁弹性传感器在不同介质、不同浓度中完成共振频率的测量,频率分辨率可达1Hz;测量不同尺寸的磁弹性传感器,所得传感器共振频率比为0.933 8,与理论值0.942 3接近;另外,与传统的阻抗分析仪搭建的组合式检测系统和现行的集成式检测系统相比,本系统工作时功耗为0.68 W,休眠时功耗仅为2.20mW。由此可见,本系统不仅能够代替原有的阻抗分析仪等组合式检测系统,而且能够大大提升现行集成式检测系统的功耗控制,兼具高集成度、便携式以及可用于长期监测等优点。

Magnetoelastic （ME） sensors, characterized by wireless, passive, low cost and high sensitivity, have widespread applications in various fields. However, its defects of large volume, high power consumption, poor portability and inconveniency for use limit the application prospects of the ME sensors. To solve this problem, the present paper shows a portable, low-power, resonance-type ME sensor detecting system based on STM32. The experimental results indicated that this detecting system allowed the ME sensor to complete the measurement of resonant frequency in different medium and different concentration, with a frequency resolution of less than 1 Hz, and the resonant frequency ratio of ME sensors in different sizes 0.933 8, closing the theoretical value of 0.942 3. Moreover, compared with the traditional impedance analyzer combined detecting system and the existing integrated detecting system, the present system has a power consumption of 0.68 W in operation and of only 2.20 mW in the dormancy mode. Therefore, the system can not only replace the original impedance analyzer combined detecting system, but also significantly improve the power control of the existing integrated detecting system, exhibiting the advantages of higher integration, portable measurement, and fine suitability for long-term monitoring.