Maximizing Energy Harvesting with Adjustable Solar Panel for BLE Beacon

Bluetooth Low Energy (BLE) beacons can be powered up with a small coin cell battery. The problem with battery-powered beacon is that frequent battery replacement is required. Such a battery replacement process can be very tedious considering the massive amount of already deployed beacons. While solar-powered beacons have emerged as an alternative to the battery-powered beacon, beacon deployment is challenging considering the very low ambient light energy available in indoor environments. This paper presents an innovate solar-powered beacon with an adjustable solar panel. In particular, we employ Markov Decision Process (MDP) to model the angle adjusting problem. The contribution of this paper is two-fold: 1) the MDP formulation is based on the insight obtained from a series of preliminary experiments which unveil the relationship between the incident angle and the harvested power; 2) our experiment shows that the legacy Policy Iteration (PI) and Value Iteration (VI) algorithms achieve similar optimized decision-making by adjusting the angle of solar panels such that to quickly charge up the beacon when it is low in energy. This rapid charging time guarantees the sustainable operation of solar-powered beacons in indoor environments.