Bicycles are known to be rich source of kinetic energy, some of which is available for harvesting during speedy and balanced maneuvers by the user. A conventional dynamo attached to the rim can generate a large amount of output power at an expense of extra energy input from the user. However, when applying energy conversion technology to human powered equipments, it is important to minimize the increase in extra muscular activity and to maximize the efficiency of human movements. This study proposes a novel energy harvesting methodology that utilizes lateral oscillation of bicycle frame (weaving) caused by user weight shifting movements in order to increase the pedaling force in uphill riding or during quick speed-up. Based on the 3D motion analysis, we designed and implemented the prototype of an electro-dynamic energy harvester that can be mounted on the bicycle’s handlebar to collect energy from the side-to-side movement. The harvester was found to generate substantial electric output power of 6.6 mW from normal road riding. It was able to generate power even during uphill riding which has never been shown with other approaches. Moreover, harvesting of energy from weaving motion seems to increase the economy of cycling by helping efficient usage of human power.

Power management systems (PMSs) are essential for the practical use of microbial fuel cell (MFC) technology, as they replace the unstable stacking of MFCs with step-up voltage conversion. Maximum-power extraction technology could improve the power output of MFCs; however, owing to the power consumption of the PMS operation, the maximum-power extraction point cannot deliver maximum power to the application load. This study proposes a practical power extraction for single MFCs, which reserves more electrical energy for an application load than conventional maximum power-point tracking (MPPT). When experimentally validated on a real MFC, the proposed method delivered higher output power during a longer PMS operation time than MPPT. The maximum power delivery enables more effective power conditioning of various micro-energy harvesting systems.