Abstract: An energy harvesting device includes at least one first magnet configured to rotate along a first circular path in a first plane. The energy harvesting device includes at least one piezo-electric cantilever spaced apart from the first plane, the at least one piezo-electric cantilever being configured to bend in a direction substantially perpendicular to the first plane. The energy harvesting device also includes at least one second magnet coupled to the at least one cantilever and configured to overlap the at least one first magnet.

Abstract: An energy harvesting device includes at least one first magnet configured to rotate along a first circular path in a first plane. The energy harvesting device includes at least one piezo-electric cantilever spaced apart from the first plane, the at least one piezo-electric cantilever being configured to bend in a direction substantially perpendicular to the first plane. The energy harvesting device also includes at least one second magnet coupled to the at least one cantilever and configured to overlap the at least one first magnet.

Abstract: A fuel cell apparatus includes: a fuel cell stack comprising a plurality of unit cells; a mixer storing a fuel mixture solution supplied to the fuel cell stack; a mixture solution sensor measuring a residual amount of the fuel mixture solution stored in the mixer; a mixture solution control pump capable of supplying the fuel mixture solution stored in a cartridge to the mixer or withdrawing the fuel mixture solution stored in the mixer to the cartridge in order to adjust a quantity of fuel mixture solution in the mixer; and a control unit receiving a residual measurement signal from the mixture solution sensor indicating both quantity and fuel concentration of the fuel mixture solution stored in the mixer, and driving the mixture solution control pump to effect the desired quantity and fuel concentration of the fuel mixture solution in the mixer.