Maximum Power Point Tracking (MPPT) for on-body Context Systems

In this article we present the use of MPPT (maximum- power-point-tracking) for miniaturized on-body activity recognition systems. We evaluate different solar cells and apply MPPT to study the suitability for on-line activity systems. With a wrist worn solar cell, MPPT allows us to track power levels of 1.35 mW for indoors/wood-workshop lighting and 7.21 mW during dull outdoor lighting conditions. The overall efficiency of the proposed technique is 96% in the best-case scenario and 80% in the worst-case.