Design of a small sized self-powered robot for monitoring the ocean water column

In this paper we present the design of a new typology of robot for sea water monitoring. The proposed robots, named JellyBots, are small-sized, `disposable' and low-cost devices for monitoring some water parameters on the water surface and along the water column. The robots are designed for long-term missions and it is envisioned they can be deployed in swarms. They are self-powered and the electrical energy is scavenged by using solar cells and by using a novel application of the thermo-generator (Seebeck effect). The robots move passively transported by sea currents and winds taking inspiration by the locomotion of the Physalia physalis jellyfish. To monitor the water parameters also in depth a variable buoyancy device was developed to modify the volume of a bladder using as source of energy the sun radiation and the sea water temperature. This system allows the robot to move passively and cyclically along the water column.