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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。
The magnetoelastic sensors with the features of wireless, passive, low cost and high sensitivity have been widely applied in various fields. However, the existing detection devices are usually bulky, high power consumption and poor portability, which limits their applicability The scope of the sensor. In this regard, this paper designed a set of STM32-based portable, low-power resonance magneto-elastic sensor detection system. The system takes the sweep frequency method as the testing basis, the STM32 as the control core, the permanent magnet as the bias magnetic field excitation, integrates the AC excitation signal unit, the signal detection and acquisition unit, and uses the SD card to store the measurement data and adopts the lithium battery for power supply. The experimental results show that the detection system can make the magnetoelastic sensor measure the resonance frequency in different media and different concentrations with the frequency resolution up to 1 Hz. The magnetoelastic sensors with different sizes are measured. The resonance frequency ratio of the sensor is 0.933 8, The value of 0.942 3 is close. In addition, compared with the integrated detection system built by the traditional impedance analyzer and the current integrated detection system, the power consumption of the system is 0.68 W and the power consumption when dormant is only 2.20 mW. Thus, the system can not only replace the original impedance analyzer and other modular detection system, but also can greatly enhance the current integrated test system power control, both highly integrated, portable and can be used for long-term monitoring and so on.