Technologies are generally described for generating electrical power from piezoelectric power. Example devices/systems described herein may use one or more of a piezoelectric device, a plurality of solid particles, and/or a container. In various examples, an electrical power generator apparatus is described, where the apparatus may be configured to provide an electrical signal upon application of a mechanical stress to the piezoelectric device. Some example apparatus may also be configured to contain the plurality of solid particles in the container, which may be coupled to at least a portion of a surface of the piezoelectric device. When a mechanical force is exerted on the plurality of solid particles, the plurality of solid particles may be effective to receive at least a portion of the mechanical force and responsively apply the mechanical stress to the piezoelectric device.

An apparatus includes an outer structure body having an inner surface defining a cavity and an inner structure body rotatably supported within the cavity. The inner structure body has an outer surface in opposing relation to the inner surface and a central bore. Movable elements are positioned along the inner surface and movably coupled to the outer structure body. Ball elements are positioned along the outer surface and coupled to the inner structure body for movement with the inner structure body. The ball elements releasably contact the movable elements and impart motion to the movable elements in response to relative motion between the inner structure body and the outer structure body. Energy harvesters are positioned to generate electrical charges based on piezoelectric effect or magnetostrictive effect when motion is imparted to the movable elements by the ball elements.

A method, apparatus and software are disclosed for wireless power transmission in which the power transmission frequency is optimised.

An energy generation device Including: a surface for supporting movement of a work material, and an energy converter. The surface is operable to induce movement of the work material relative to the surface. The energy converter is arranged to generate electrical energy based on the induced movement of the work material relative to the surface.

A device (10) for converting a movement of a user into a voltage comprises a neck cord (20), a piezoelectric sensor (30) and a printed circuit board (40). The neck cord is coupled to the piezoelectric sensor and provides in use a pulling force that acts on the piezoelectric sensor in a first direction. The printed circuit board is electrically and mechanically coupled to the piezoelectric sensor. The weight of the printed circuit board cause in use a gravity force to act on the piezoelectric sensor in a second direction, which differs from the first direction such that the movement of the user (5) wearing the neck cord causes a change in the shape of the piezoelectric sensor which in response thereto generates the voltage. The voltage may be used as a supply source for an electrical component (41) mounted on the PCB, or may be used as a wake-up signal for an electrical component such as a processor (41) or an accelerometer.

A device responsive to an acceleration pulse event, the device including: a piezoelectric device configured to generate a voltage over a duration responsive to one or more acceleration pulse events; an electrical storage device configured to receive a portion of the generated voltage to accumulate a charge; an energy dissipating device coupled to the electrical storage device and configured to dissipate the accumulated charge following the one or more acceleration pulse events and not to substantially dissipate the accumulated charge during the one or more acceleration pulse events; and a voltage limiting device coupled to the electrical storage device and configured to limit the portion of the generated voltage applied to the electrical storage device to a predetermined limit.

A number of devices are described which can be used to generate electric power from the action of wind or other sources of vibration. The devices comprise Piezo electric materials, which are built into the devices in a way that can capture the generated electric power, and can conduct it to storage devices. Several embodiments are described.

A self-powered sensor system and sensing method includes a power source generating power which is a function of a first parameter such as vibration. A charge management circuit is responsive to the power output by the power source and is configured to provide, every charge cycle, a supply signal to a controller which activates it to control a transmitter to transmit data at a transmission rate which is a function of the charge cycle. The data and the transmission rate are processed and used to identify a variation in the first parameter by a variation in the transmission rate beyond a predetermined threshold.

A vibrational multi-morph piezoelectric energy harvester includes a composite shim having a parallelepiped form with a thickness dimension made smaller than width and length dimensions, and having a stiffness shifting from one extremity to the other extremity to minimize mechanical constraints developed at a clamping area; a seismic mass mounted at an end opposite to the clamping area to mechanically match the system to the surrounding vibration resonance; one or more piezoelectric layers laminated on said composite shim; and electrodes plated onto the one or more piezoelectric layers for connection to an electronic harvesting circuit, a battery, or a super capacitor.

The module comprises a pendular unit with an elastically deformable piezoelectric beam having a clamped end and an opposite, free end, coupled to an inertial mass. The beam produces an oscillating electrical signal collected by electrodes, which is rectified and regulated to output a voltage for charging a battery. The number and configuration of the electrodes (T1, T2, B1, B2, N) carried by the piezoelectric beam define a plurality of pairs of electrodes between which a corresponding plurality of said oscillating signals can be simultaneously collected. A switching matrix, as a function of an input command, selectively switches the plurality of pairs of electrodes between each other according to a plurality of different series (S), parallel (P) and/or series-parallel (SP) configurations, the selected configuration being that which maximizes the power sent to the battery as a function of the voltage level (VBAT) present at the terminals of the latter.