A battery-free, wireless underwater camera

Scientists estimate that more than 95% of Earth's oceans have never been observed, which means we have seen less of our planet's ocean than we have the far side of the moon or the surface of Mars.

Researchers have developed a battery-free, wireless underwater camera that is about 100,000 times more energy-efficient than other undersea cameras. The device takes color photos, even in dark underwater environments, and transmits image data wirelessly through the water.

The autonomous camera is powered by sound. It converts 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.

It could also be used to capture images of ocean pollution or monitor the health and growth of fish raised in aquaculture farms.

This technology could help to build more accurate climate models and better understand how climate change impacts the underwater world.