Insole Pedometer With Piezoelectric Energy Harvester and 2 V Organic Circuits

A shoe insole pedometer, which consists of a piezoelectric energy harvester and a 2 V organic pedometer circuit, has been developed as a first step toward the application of flexible large-area energy harvesting. A pseudo-CMOS 14 bit step counter records the number of steps up to 16383 steps using the harvested power. To increase the noise margin of the pseudo-CMOS logic circuits, a negative voltage is generated by an organic charge pump circuit and is applied to the pseudo-CMOS inverters and transmission gates in the flip-flops in the step counter. A pseudo-CMOS Schmitt trigger inverter used to feed clean square pulses to the step counter is presented. This paper describes the details of the insole pedometer and provides measurement results and some discussion.