Finding new energy sources has received in recent years a particular interest among scientists. Our research focuses on the generation of micro-renewable energy. This energy is used to power various wireless devices, such as sensors, actuators and micro-electromechanical systems (MEMS). In this work, a new innovative form of piezoelectric harvester, using PVDF polymer, has been proposed, “piezo-spring”. Their time deformation gives a time signal, useful for applications that need an instantaneous electrical signal. Materials and geometry were chosen such as to increase the stiffness of the spring and by this the piezoelectric conversion. A numerical simulation of the use of this device in a keyboard application was carried out using finite element calculation software. A power value in the range of 0.625 µW was obtained at a 10 Hz frequency.