Practical Node Design for Wireless Multi-Hop Network Applications in Oyster Farming

In recent years, the application of Internet of Things (IoT) technologies has advanced in agriculture, forestry, and fisheries. In this paper, we focus on the hatchery phase of oyster farming and consider a wireless multi-hop network to realize a system that monitors water quality and ambient temperature/humidity in real time using sensors. We design a fully waterproof, integrated device that combines a water quality sensor with a wireless communication module, enabling direct submersion in water for flexible and practical use. However, since radio signals significantly attenuate underwater, we first conduct preliminary experiments using actual hardware to evaluate the affect quantitatively. We then propose to introduce a cylindrical container as a waveguide to improve communication range. Finally, we prototype a wireless multi-hop network and confirm its feasibility.