Abstract
We have proposed the thin plate type bolt loosening detection sensor. However, the sensor is too large for practical use, so that it is desired to miniaturize the sensor. In this paper, we propose slit cut thin plate type sensor as a miniaturized sensor and the oscillator circuit for natural frequency identification. The size of the slit cut sensor is smaller than the quarter size of the thin plate sensor. The oscillator circuit is based on positive velocity feedback and the oscillating frequency of the circuit coincides with the natural frequency of the sensor perfectly.
