About 71 percent of the earth’s surface is covered with water, and the oceans hold 96.5 percent of water. According to scientists, more than 80 percent of the ocean has never been explored or mapped. Contradictorily, we have discovered a high percentage of the moon and Martian surfaces besides our water bodies on earth.
Keeping this in mind, researchers at the Massachusetts Institute of Technology, U.S., have developed a wireless and battery-free camera (currently a prototype) that can help in underwater exploration and track the effects of climate change.
Insights into the camera
When it comes to oceanography or undersea exploration, powering an underwater camera for a long duration is one of the major problems. Generally, this is done by attaching it (camera) to a research vessel like a submarine or boat or sending a ship to recharge batteries. But this newly developed camera is 1,00,000 times more energy-efficient than conventional underwater cameras and doesn’t require batteries for recharging. This device can take coloured images even in the dark and transfer data wirelessly through the water.
The device gets power from the sound. It converts mechanical energy from sound waves in the water to electric energy that provides power to its imaging and communication system. After collecting image data, it uses sound waves to transfer this data to a receiver that recreates the image. As the device doesn’t require a power source, it can work for several days, allowing oceanographers to visit inaccessible parts of oceans for research purposes. Further, it can also be used for monitoring water pollution and identifying new aquatic species.
The making of the battery-free camera
To make a self-reliant energy-independent camera, researchers required a device that could create energy on its own underwater using less power. The researchers added transducers into the camera made from piezoelectric materials that generate electricity from mechanical energy when a sound wave travelling in the water hits transducers. These sound waves can come from any passing by ships or marine transport. The device stores captured energy until it generates sufficient power to work and set up a communication system.
Image Credits: Wikimedia
The researchers used ultra-low power imaging sensors to minimise energy consumption. However, these sensors could only detect grayscale images (pictures having white, grey and black colours only). Further, most underwater areas lack light, so they had to develop a low-power flashlight.
For both issues, they used red, green and blue LED lights. When the camera clicks images, a red LED shines and then image sensors take the picture. Though the photos look black and white, the coloured LED light is captured in the white part of the photo, and during the image reconstruction process, coloured pictures can be obtained.
Working with sound
The camera uses the binary system for data collection and image reconstruction. When image information is captured, it is sent to the receiver in the form of bits (0 and 1). The receiver transfers sound waves to the camera via water. Then, the camera either reflects a wave or absorbs the transferred energy and doesn’t reflect. The transmitter has a hydrophone that can sense signals or waves. If the camera sends a signal, it is encoded in bit-1, and if it doesn’t, it is represented in bit-0. Currently, the researchers are working on increasing the camera’s memory so it can capture stream images, videos, etc., along with its image-capturing range.
The research has been published in the journal Nature Communications.
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