Fear of the Dark: Exploring PV-Powered IoT Nodes for VLC and Energy Harvesting

Implementing Visible Light Communication (VLC) in underwater operations is crucial for many applications (e.g., marine research, environmental monitoring, etc.). While acoustic communication is typically used for long-distance underwater links, it entails expensive hardware makes it unsuitable for pervasive measurement systems. VLC, although offering a limited range, lowers the costs and supports multi-hop communication, making it ideal for underwater monitoring. Pervasive VLC systems in remote and harsh environments should be self-powered to improve operability and reduce onsite maintenance. This study explores a self-powered Internet of Things (loT) sensor node with VLC capabilities, also addressing potential cyber-security threats. The node features a tandem solar cell for both energy harvesting and data reception, and embeds a white LED for transmission, so to enable energy harvesting and VLC reception by absorbing a broad light spectrum. The system proves the feasibility of using tandem solar cells for underwater VLC, achieving communication up to 10 m while harvesting sufficient energy to power an IoT sensor node. These results are preliminary, though, with future works needed to address factors like salinity, obstacles, and turbidity.