Bluetooth Low Energy (BLE) beacon device becomes a key component to form the IoT infrastructures for many smart city applications today. However, a regular BLE beacon device always has a limited lifetime due to the use of the battery. Hence, such infrastructures will involve a lot of cost and manpower for the maintenances. With the photovoltaic energy harvesting technologies, some BLE beacon devices could be possibly powered by solar or even light energy in the outdoor and indoor environments. Unfortunately, these solar-powered BLE beacon devices generally do not harvest enough energy for the required operations, as the angles of light sources in an indoor or outdoor environment is not always favorable for their best possible harvesting performances. To address this challenge, our resea...[ Read more ]

Bluetooth Low Energy (BLE) beacon device becomes a key component to form the IoT infrastructures for many smart city applications today. However, a regular BLE beacon device always has a limited lifetime due to the use of the battery. Hence, such infrastructures will involve a lot of cost and manpower for the maintenances. With the photovoltaic energy harvesting technologies, some BLE beacon devices could be possibly powered by solar or even light energy in the outdoor and indoor environments. Unfortunately, these solar-powered BLE beacon devices generally do not harvest enough energy for the required operations, as the angles of light sources in an indoor or outdoor environment is not always favorable for their best possible harvesting performances. To address this challenge, our research has proposed two effective and practical solutions. Firstly, a BLE beacon device with an adjustable angle of solar panel is introduced. A Markov decision process is employed to learn the changes of harvestable energy in an environment over time, so that the BLE beacon device can adjust the solar panel accordingly for the best harvesting performance. Secondly, a practical design of BLE beacon device with one-time adjustable angle of solar panel is introduced, which employs a new model that can estimate the combined energy being harvested in an environment with both the indoor and outdoor light sources. Hence, such one-time angle adjustment is determined for the BLE beacon device for the most practical and cost-effective deployment manner and better energy harvesting performance over time. Our proposed works and research prototype are verified with the real deployments in different environments. The experimental results proved that our proposed works can outperform conventional solar-powered BLE beacon devices for much better energy harvesting performances.