This study used the Design for Assembly (DFA) and material selection methods as tools to aid the development of a conceptual design of a functional device to transform alternate movement into rotational movement on the axis of a microgenerator. Also, material selection software was used to define the most suitable thermoplastic materials for some components of the projected device, focusing both on performance and low cost. There was a considerable reduction in the number of parts in the set from the basic device (prototype), which had 47 parts, to the conceptual design I, with 34 parts, and the conceptual design II, with 14 parts. The total mass of the set was also considerably reduced, from 160 grams for the basic device to 57.01 grams in the conceptual design I and, finally, 18.30 grams in the conceptual design II. Of thermoplastic materials analysed, considering a selection focused only on performance the most promising candidate, with an ideal set of properties is PEEK. But for a selection that considers the price, that is one of the key variables in the materials selection for most products, PEEK shows is prohibitively price.