A significant challenge for undersea exploration is powering underwater cameras. Researchers can tether it to their vessel or send a ship and diver to recharge its batteries. MIT researchers are overcoming the challenge, developing a battery-free, wireless, underwater camera that is approximately 100,000x more energy-efficient than other undersea cameras. It yields color photos, even in dark aquatic environments, and transmits image data wirelessly through the water.
Powered by sound, the camera converts mechanical energy from sound waves traveling through water into electrical energy that powers its imaging and communications equipment. The camera also uses sound waves to transmit data to a receiver that reconstructs the image. They published their paper in Nature Communications.
The camera acquires energy using transducers made from piezoelectric materials placed around its exterior. When a sound wave traveling through the water hits the transducers, they vibrate and convert that mechanical energy into electrical energy. The camera stores harvested energy until it builds up enough to power the electronics that take the photos and communicate the data.
They used off-the-shelf, ultra-low-power imaging sensors and developed a low-power flash. When the camera captures an image, it shines a red LED and then uses image sensors to take the photo. It repeats the same process with green and blue LEDs. The researchers tested the camera in several underwater environments.
The device could help scientists explore unknown regions of the ocean, track pollution, or monitor the effects of climate change.
