Acceleration sensor device and sensor network system

摘要

To provide an acceleration sensor and a sensor network system having a construction in which the consumption of power to be consumed can be reduced and the sensor itself can be miniaturized without using any piezoelectric sensor or piezoelectric bimorph.;An acceleration sensor device provided with an acceleration sensor which is an electrostatic induction conversion device for conversion between electric energy and kinetic energy, which comprises a conductor and an electret moving relatively to the conductor, said acceleration sensor device having: an acceleration detection unit to detect a signal corresponding to acceleration, from an AC voltage output by the acceleration sensor; a rectification unit to rectify the AC voltage; and a power supply circuit having a battery to power circuits in the device to work, to charge the battery with the rectified voltage as electric energy.

主权项

1. An acceleration sensor device provided with an acceleration sensor which is an electrostatic induction conversion device for conversion between electric energy and kinetic energy, which comprises a conductor and an electret moving relatively to the conductor, said acceleration sensor device having:
an acceleration detection unit to detect a signal corresponding to acceleration, from an AC voltage output by the acceleration sensor; a rectification unit to rectify the AC voltage; and a power supply circuit having a battery to drive circuits in the device and adapted to charge the battery with the rectified voltage as electric energy, wherein the acceleration sensor device further has: an abnormal vibration-detecting circuit which compares the rectified voltage with a preset threshold voltage to output an abnormal signal notifying an abnormality when the rectified voltage exceeds the threshold voltage, a recording circuit which is activated by the abnormal signal output by the abnormal vibration-detecting circuit as triggered by an abnormal vibration detected by the acceleration detection unit, to start recording a signal corresponding to acceleration; and which terminates the recording at a preset timing, and a determination unit to determine whether the abnormal vibration is a vibration which should be recorded, by comparing an objective vibration pattern consisting of the frequency of the signal corresponding to acceleration and the spectrum intensity corresponding to the frequency, with a preset reference vibration pattern consisting of a frequency and its corresponding spectrum intensity to determine by the comparative result whether the signal corresponding to acceleration should be recorded.