Strain Gauge-Enable Wireless Vibration Sensor Remotely Powered by Light

This paper presents a low-power wireless strain sensor that can be remotely powered by a light source and can be dynamically interrogated with a low-cost wireless interrogator. Based on a conventional thin-film strain gauge, the wireless sensor is capable of measuring both static and vibration deformations. The low-power wireless operation was achieved via amplitude modulation of the antenna backscattering using a high-frequency oscillatory signal, whose frequency is controlled by the low-frequency strain signal. The wireless strain sensor can be powered continuously by harvesting the energy supplied from a remote light source using a small solar panel. A microprocessor-based wireless interrogator was developed to recover the strain information from the wirelessly received signals dynamically. The implementation and characterization of the wireless strain sensor and wireless interrogator are presented.