There is a growing demand for micro energy harvesting from environmental mechanical vibrations for self powered sensor technologies. Piezoelectric crystals, typically clamped at one end with a cantilevered weight at the other, generate electricity when mechanical oscillations occur at or near their resonant frequency. However torsional (rotational) vibrations produce no electricity as the left and right sides of the crystal are flexed in opposite directions creating a net zero voltage.
The present invention describes a simple geometry, electrically isolating left and right sides of the crystal so their voltages generated can be summed rather than cancelled. This allows a X 100 increase in power generated.
A patent application has been submitted.
Inventor: Dr. Lijie Li