Underwater Camera

Sound Waves Power This Battery-free Underwater Camera

One hundred thousand times more effective than other underwater camera systems, scientists have created an underwater camera that is only powered by sound waves.

Although seafloor cameras are useful for monitoring wildlife, for example, powering and obtaining their images may be difficult. A new camera developed by MIT can aid in this because it wirelessly transmits images through the water and runs on no batteries.

The camera does not have a battery or a long power cord; instead, a series of piezoelectric transducers are placed thoughtfully all over its exterior.

How Does It Work?

The pressure created by sound waves from sources such as animals or watercraft causes special materials inside the transducers to vibrate. Those substances produce an electrical current when shaken because they are piezoelectric. After creating enough electrical energy in this manner and storing it in a super-capacitor, it is then used to take a picture.

To cut down on power usage, engineers used commercially available, ultra-low-power imaging sensors. However, these sensors can only be used to capture grayscale images. They also needed to create a low-power flash because most underwater environments are dark.

“There are new limitations on how to construct the system, send data, and perform image reconstruction as a result of our efforts to minimize the hardware as much as possible. It took a fair amount of creativity to figure out how to do this,” said Fadel Adib, associate professor.

Tackling Limitations

Each color image consists of three fundamental color exposures—one with red LEDs, one with green LEDs, and another with blue LEDs—to get around this restriction. Each exposure gives the impression of being in black and white, but actually shows the subject’s ability to reflect red, green, or blue light. As a result, when all three photos are analyzed and combined, a single composite color image can be created.

In order for the camera to wirelessly receive the digital image, which is encoded as a string of 1s and 0s, a surface-based transceiver sends quick sound-wave signals through the water. In response, a module in the camera either signals a 1 by reflecting the signal to the transceiver or a 0 by absorbing the signal. As a result, a topside computer may keep track of which signals are reflected to the transceiver and which are not in order to store a pattern of 1s and 0s that represents the color image.

Future Plans

The device has so far been used successfully for tasks like tracking an aquatic plant’s growth in a dark environment for a week. It has a maximum underwater range of 40 meters (131 feet). The MIT team is presently working to expand the battery-free camera’s memory and range in order to feed real-time images, stream images, and even record full-motion underwater video.

The technology could aid in the exploration of uncharted ocean regions, the tracking of pollutants, and the monitoring of climate change’s effects. The development of fish raised in aquaculture farms could also be observed. “This technology could help us build more accurate climate models and better understand how climate change impacts the underwater world,” said Adib.

Haitham Al-Hassanieh, an electrical and computer engineering assistant professor at the University of Illinois Urbana-Champaign, who was not involved in the study, added:

“This will create excellent opportunities for research in low-power IoT devices as well as monitoring and study of the ocean floor.”

The results of the study were published in the journal Nature Communications on September 26, 2022. Images from a camera test are shown in the video that follows.

Related Reading: Best Underwater Fishing Camera

Source: Intelligent Living

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