Abstract: An electrostatic induction-type vibration power generation device and method for improving a power generation amount, and extracting an external electric field from a spontaneous polarization electret. A pair of conductive plates is disposed with a gap therebetween. A charged body formed of a spontaneous polarization electret having predetermined thickness has a positively charged lower surface and negatively charged upper surface. The charged body is between conductive plates in contact with one conductive plate. The gap between the conductive plates is displaced in a direction vertical to the surfaces of the spontaneous polarization electret, whereby an electrostatic capacitance changes and electric power is generated. The other conductive plate is disposed at a position where an absolute value of an external electric field emitted outside from the charged body is between 2.7×107 V/m and 1.5×1010 V/m. Moreover, the thickness of the spontaneous polarization electret is between 1 mm and 60 mm.

Abstract: A sensor device for sensor networks capable of saving power and securing accuracy and a method for transmitting data to a sensor network. The device includes: an oscillation-type sensor that oscillates with a mechanical vibrator; a data processor and communicator that processes a signal output from the oscillation-type sensor and transmits data to an external apparatus; a power supply that supplies electric power to the oscillation-type sensor and the data processor and communicator; and a power supply control unit that controls connection of a power supply line between the power supply and the oscillation-type sensor and connection of a power supply line between the power supply and the data processor and communicator. The power supply control unit connects the power supply line between the power supply and the oscillation-type sensor and then connects the power supply line between the power supply and the data processor and communicator.