System uses ultrasound to transmit data through metal

A doctoral student at Rensselaer Polytechnic Institute has developed a system that uses ultrasound to simultaneously transmit large quantities of data and power wirelessly through thick metal walls, such as the hulls of ships and submarines.

For his efforts, Tristan Lawry, a student in Rensselaer Polytechnic’s Department of Electrical, Computer, and Systems Engineering, is one of three finalists for the 2011 $30,000 Lemelson-MIT Rensselaer Student Prize.

To install critical safety sensors on the exterior of ships and submarines the US Navy is forced to drill holes in the hull through which cables for data and power transmission are run. Each hole increases the risk of potentially serious issues, including leaks and structural failure.

Lawry’s invention solves this problem. Unlike conventional electromagnetic wireless systems, which are ineffective at transmitting power and data through vessel hulls because of the “Faraday cage” shielding effects they present, his can propagate signals through thick metals and other solids. Lawry’s design features separate non-interfering ultrasonic channels for independent data and power transmission.

With this new system, Lawry has demonstrated the simultaneous, continuous delivery of 50W of power and 12.4Mbit/sec of data through a 2.5in-thick solid-steel block in real time. These results are claimed to surpass all known previously published systems capable of simultaneous data and power transmission through metal.

With only minor modifications, Lawry said he is confident his design will have the capacity to support much higher power levels and data rates. His design also allows the transmission system to adapt to non-ideal conditions and mechanical variations over time.