Given limited resources and the growing of population in the world, the rational and efficient use of energy stands as a priority in energy planning instead of just a topic in vogue; any effort in this sense really matters. For example, in this paper, we present the design and implementation of a prototype to harvest energy, from the rotation in a handle to a NiMH battery. The handle rotates the shaft of a generator, through a set of gears, transforming mechanic energy into electrical energy. Then, a supercapacitor stores the electrical energy that recharges the battery by means of an electronic circuit. In particular, the full charge of the battery of 700 mAh requires 74 transfers from the supercapacitor.