An Energy Harvester Interface for Self-Powered Wireless Speed Sensor

This paper presents an innovative electromagnetic energy harvester and its power interface to power wireless speed sensor used in bicycles. The self-powered wireless speed sensor does not need maintenance, since it does not use pollutant batteries that must be replaced. The energy harvester is made up of a coil that takes energy from the wheel's rotation and at the same time, it senses the wheel revolution. This energy is enough to elaborate and transmit speed data to nearby devices, such as smartphones using low-power RF protocols. A prototype of the electromagnetic energy harvester was built and the harvested energy was measured. Furthermore, a power interface circuit based on passive voltage doubler and low power dc/dc regulator was designed. Finally, the power interface, some energetic consideration, and the feasibility of the sensor were validated using SPICE simulations.