부산대학교 도서관

The Internet of Underwater Things (IoUT) will enable new military, scientific, and commercial applications at sea. However, powering of electronic devices in deep water still remains one of the main challenges, since these systems are typically powered by traditional batteries. This article presents the design of the first batteryless underwater sensor node that can be wirelessly recharged through ultrasonic waves from longer distances than allowed by current technologies. First, the architecture of an underwater platform capable of extracting electrical energy from ultrasonic waves is introduced. We then illustrate how to interface this system with an underwater digital communication unit. We discuss the design of a prototype where the storage unit is realized with a batch of supercapacitors. We show through experiments that the harvested energy is sufficient to provide the sensor node with the power necessary to perform a sensing operation and power a modem for ultrasonic communications. In the article, we evaluate the system power transfer efficiency. Given the reduced attenuation of ultrasonic waves in water, we show that our approach can cover longer distances with less transmission power than alternative solutions. Last, we experimentally evaluate the overall operating efficiency of the system.