Energy harvesting for bladder pressure sensor using parametric amplification phenomenon of PVDF bimorph cantilever

In this paper, we identify feasibility of energy harvesting using parametric amplification phenomenon of piezoelectric bimorph cantilevers for bladder pressure sensing. We simply fabricated piezoelectric bimorph cantilevers by bonding 110 µm thick polyvinylidene fluoride (PVDF) and 500 µm thick polycarbonate (PC) using an epoxy. The piezoelectric bimorph cantilever was 34.8 mm long, 10 mm wide, and 0.8 mm thick and exhibited resonance frequency of ∼150 Hz. By applying twice the fundamental frequency excitation, we obtained the voltage generated in the piezoelectric bimorph cantilevers at the fundamental frequency. Maximum voltage was generated when the direction of excitation is parallel to the vibration of the cantilever. Maximum power harvested using the parametric amplification phenomenon was measured to be 6.05 nW.