In this paper, we designed and fabricated electromagnetic induction based scaffold type energy harvester. For energy harvesting, mechanical energy of vertical motion is transferred to rotational energy using rack gear and multiplying gear was used to maximize energy transfer. To optimize design parameters, physical structure of energy harvester was modeled using finite element method. The effect of multiplying gear ratio and frequency levels of applied mechanical energy on energy generation efficiency are analyzed by computer simulation and experimental test. Experimental results showed that maximum 25.36 W of electric power can be achieved at the frequency of 2 Hz and 1:77 of gear ratio with only 5 mm of vertical changes on scaffold structure.

Recently, energy harvesting technologies are considered as the great alternatives to reduce the dependency on secondary batteries. In this paper, we proposed PCB type energy harvester which can be directly integrated with other electronic components on same board. To form the three dimensional coil structure, two PCBs with patterned metal lines are solder bonded. For magnetic induction, inside of coil structure was filled with magnetic substance and rotary motioned external magnets are applied to near the harvester. The effects of metal wire width on PCB, thickness of magnetic substance, and frequency of rotary motion on energy harvesting performance are analyzed by computer simulation and experiments. Experimental results showed 29.89 ㎼ of power generation performance at the frequency of 5.2 Hz and it is shown that designed harvester can be effectively applied on vibration environment with very limited frequency.