Designing a piezoelectric energy harvester using clicking mechanism

Abstract

Many researches on developing new energy sources are being actively conducted recently. These new energy sources include renewable energy sources such as solar, wind, rain or wave energy and harvesting energy especially from human activities. In this research, we developed an energy harvester using human footsteps among various sources of energy. This energy harvester generates electricity by hitting and vibrating piezoelectric cantilever beams. It can be applied to stairs or sidewalks to produce electricity from human footsteps. We manufactured the energy harvester having a dimension of 200 × 200 × 160 mm3. There were four piezoelectric beams in the harvester. An experiment was conducted with a man pressing the harvester. When the harvester is pressed and released once, the hitting stick rotates 180°. We measured the output power caused by hitting and vibrating the piezoelectric beams. An impedance matching was conducted and the matched resistance turned out to be 1 kfí and at this value, the average voltage became 7.62 V rms and the average power, 58.06 mWrms. The peak voltage was 18.44 Vpeak and the peak power was 340.03 mW peak at the moment.