Micro-electro-mechanical-systems (MEMS) impact everyone every day. Mobile phones, laptops, hearing aids, watches, automotive and medical devices are only few examples of portable goods that include MEMS. Such products mostly rely on batteries as their source of power, and the need for battery replacement/recharging, and environmental concerns, are increasingly an issue. Harvesting energy from every day motion, otherwise left unused, is a recent approach to supply energy for portable goods, ranking as one of the current top 10 technologies according to EE Times. Nevertheless, the energy efficiency of energy harvesters has not been sufficient thus far, particularly if the harvesters are not operating in their natural frequency. In addition, energy harvesting is a cross-disciplinary field with both structural and electrical challenges creating additional difficulties in solving the energy efficiency problem. This research proposal aims at tackling both mechanical and electrical challenges at the same time. The stiffness of the MEMS energy harvester will be removed, or tuned to a pre-defined nonlinear behaviour using static balancing theory. This is an entirely new approach the present applicant has been working with for the last four years at Delft University of Technology. The electronic tuning will be achieved via the transducer, a method for which the host group at Imperial College London is famous. The present proposal shall develop an efficient energy harvester to harvest from low and wide range frequency of human body motion. Being a straightforward method, this approach is not only essential for MEMS medical devices, but will also serve as a framework to guide other industrial applications.