System and method for charging batteries with ambient acoustic energy

Abstract

A system and method for charging rechargeable batteries using power from ambient acoustic waves. A first embodiment comprises a system with one or more audio speakers and a battery charger. Each speaker has a transducer that generates an electromotive force (EMF) in response to acoustic waves incident on the speaker. The battery charger receives the EMF from the speaker and charges one or more batteries using the received EMF. A second embodiment comprises a method for charging rechargeable batteries by the steps of generating a sound wave incident on an audio speaker, the speaker generating an EMF, providing the EMF to a battery charger, and the battery charger using the EMF to charge the batteries. A third embodiment comprises a battery charger that uses electrical power generated by one or more audio speakers to charge one or more rechargeable batteries. A rectifying unit in the battery charger receives and rectifies EMFs from the speakers and provides it to the batteries. In a fourth embodiment, the invention comprises a portable telephone, preferably a cordless telephone or a cellular telephone, with a battery charger that uses acoustic energy incident on the speaker of the portable telephone to charge batteries in the telephone. A fifth embodiment of the present invention comprises a portable electronic device, such as a portable radio, a tape recorder, or a hand-held video game, that uses acoustic energy incident on a speaker or microphone to charge batteries in the portable electronic device.