Battery-less Place Recognition System using Multiple Energy Harvesting Elements

We propose a room-level place recognition system which uses energy harvesting elements as both sensor and power source. As energy harvesting elements, we focus on solar cells. In our previous work, by combining multiple types of cells and learning the difference of the generated power, we succeeded to distinguish ten places thanks to different characteristics of solar cells according to their materials. However, since the previous research focused on investigating the feasibility of our fundamental idea, it used a microcomputer board that requires an additional battery to measure the amount of generated power. Hence, it did not reach the level to utilize the energy harvesting elements as a power supply required for running the whole system. In this paper, we re-design our previously proposed mechanism to measure the amount of generated power of the energy harvesting elements and propose the novel mechanism to measure the amount of generated power by using the generated power without any additional battery. In stead of measuring the amount of generated power, our system has the circuit that counts how many times the electrolytic capacitor has been fully charged. The capacitor used is the minimum size required for reading the time stamp and write it to the memory. Finally, we can measure the amount of generated power by counting the time stamps recorded per unit of time. We designed and implemented the new circuit on PCB, and applied our system to room-level place recognition. As a result, we confirmed that our system can accurately distinguish the eight places.