Abstract: A miniature energy harvesting device for producing electricity from acoustical energy, stray electromagnetic energy, noise and from energy of different anatomical motions. The device comprises a housing, a mechanical spring engaged with the housing between a static and dynamic state and a first magnet engaged with the mechanical spring. The device further comprises a conductive grid freely moveable within a cavity of the housing. The device further comprises a composite structure comprising a fixed magnet and a piezoelectric material. The composite structure is engaged with the grid and in communication with the first magnet. The first magnet and the fixed magnet apply a force upon the piezoelectric material when the mechanical spring is in the static state to produce a base voltage. Excitation of the mechanical spring causes the piezoelectric material to generate an alternating voltage output having a peak voltage greater than the base voltage.

Abstract: A miniature energy harvesting device for producing electricity from acoustical energy, stray electromagnetic energy, noise and from energy of different anatomical motions. The device comprises a housing, a mechanical spring engaged with the housing between a static and dynamic state and a first magnet engaged with the mechanical spring. The device further comprises a conductive grid freely moveable within a cavity of the housing. The device further comprises a composite structure comprising a fixed magnet and a piezoelectric material. The composite structure is engaged with the grid and in communication with the first magnet. The first magnet and the fixed magnet apply a force upon the piezoelectric material when the mechanical spring is in the static state to produce a base voltage. Excitation of the mechanical spring causes the piezoelectric material to generate an alternating voltage output having a peak voltage greater than the base voltage.

Abstract: The present invention is an energy harvester having a mechanical natural frequency that can be mechanically tuned to the natural frequency of the vibrating environment without having to add or subtract mass to seismic/proof mass, change the mass of the mechanical spring or change the physical dimensions of the mechanical spring of the energy harvester. In another embodiment, the electromagnetic natural frequency of the energy harvester is electronically tuned by adding a tuning circuit comprising a variable dissipative element without changing the mechanical natural resonant frequencies of the energy harvester.