Despite all the technological advances, our knowledge of the oceans are still very limited. In order to study the seabed, researchers from the Massachusetts Institute of Technology (MIT), in the United States, have managed to create an autonomous underwater camera, which works completely without batteries and communicates wirelessly, without emitting waves. They detailed their invention in the review. NatureCommunications.
To power the camera, the device uses a transducer, made with piezoelectric materials, which converts sound waves into electricity. These waves are transmitted through the water from a base station. The power obtained is of the order of a few tens to a few hundred microwatts. This energy is stored in a supercapacitor until you reach the threshold needed to take or transmit photos.
Extremely low consumption
With such a power supply, the camera must necessarily have a very low power consumption. To achieve this, the researchers opted for a commercial ultra-low power monochrome sensor (Himax HM01B0). To obtain color images, the device is equipped with three LED diodes: one red, one blue and one green. The camera then takes three photos, one with each lighting color. They are then combined to form a single color image.
To transmit the photos, the researchers were unable to use an existing underwater communication system. These use at least 50 to 100 milliwatts, or a thousand times the energy harvested by the transducers. They reduced the consumption to a few nanowatts using a technique that does not emit a signal: backscatter (Where backscatter). With this method they managed…