Sound-powered camera

MIT researchers have developed a battery-free, wireless underwater camera that is about 100,000 times more energy efficient than other undersea cameras. It takes color photos, even in dark underwater environments, and transmits image data wirelessly through the water, with a 40-meter range that they are working to improve.

The autonomous camera uses piezoelectric materials to convert mechanical energy from sound waves traveling through water into electrical energy that powers its imaging and communications equipment. After capturing and encoding image data, the camera also uses sound waves to transmit data to a receiver that reconstructs the image.

Because it doesn't need a power source, the camera could run for weeks on end before it is retrieved, enabling scientists to search remote parts of the ocean for new species. It could also be used to capture images of ocean pollution or monitor the health and growth of fish raised in aquaculture farms. Tracking the effects of climate change is another important potential application.

This technology could help us build more accurate climate models and better understand how climate change impacts the underwater world," says Fadel Adib, associate professor in the Department of Electrical Engineering and Computer Science and senior author of a paper on the system, who notes that more than 95% of Earth's oceans have yet to be observed.