Energy harvesting from flexible piezoelectric ring

Herein, we investigated the feasibility of a flexible ring type energy harvester for a cylindrical shape change similar to that in a bent human finger. We fabricated a ring type energy harvester using a piezoelectric material, polyvinylidene fluoride, on a polydimethylsiloxane substrate. We modeled a human finger using a silicone cylinder to mimic the movement of a real human finger and measured the power harvested from its shape change under compression. A series of experiments were conducted under two different conditions, namely the variations in the radius of the cylinder and input frequency. Furthermore, we experimentally and theoretically assessed the output power and analyzed the harvested power as a function of the load resistance. We observed that the maximum harvested power level is of the order of hundreds of nanowatts.