Bio-Implantable piezoelectric energy harvesting from acoustic power transmission

Implantable - piezoelectric - acoustic power

We report on a novel electromechanical energy scavenging and wireless interrogation scheme using low frequency components of musical vibrations. The device incorporates a piezoelectric cantilever beam that converts the acoustic vibrations into electric power; rectifying circuitry; a storage capacitor in parallel with a PDMS based inductive pressure sensor; and a ferrite core. Musical sound wave from a loudspeaker induces vibrations in the piezoelectric cantilever at harmonics, which match its resonant frequency. This, in turn generates a voltage that is rectified and stored in the capacitor. At non-resonant harmonics, the supply is interrupted, causing the stored charge to be dumped into the sensing LC tank inducing oscillations at its natural frequency, which is picked up externally with a receiver coil. Applying pressure reduces the distance between the ferrite core and the coil, changing the inductance and hence modulating the resonance frequency of the LC tank.

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