Engineers from Columbia University’s Computer Vision Laboratory have created what they claim to be the world’s first fully self-powered camera. The self-contained, solar-powered video camera converts light captured when creating an image into electrical power. While the prototype captures only one image per second of a well-lit indoor scene (as opposed to the standard video camera capture of 30 frames per second), the developers hope that their camera may pave the way for more self-powering electrical devices, such as phones and watches.
In a press release, the team explained that project leader Shree K. Nayar, director of the Computer Vision Laboratory at Columbia Engineering “realized that although digital cameras and solar panels have different purposes—one measures light while the other converts light to power—both are constructed from essentially the same components. At the heart of any digital camera is an image sensor, a chip with millions of pixels.”
The key component of any pixel in a digital camera is the photodiode, which produces electrical current when exposed to light. In a camera, that measures the incident of light falling on it, provides information as to aperture and exposure, and captures an image. But the same photodiodes are also key components in solar panels, where they convert that light to power. In short, the “photodiode in a camera pixel is used in the photoconductive mode, while in a solar cell it is used in the photovoltaic model.”
The team used off the shelf components to create a 30×40 pixel image sensor, housed in a 3D-printed body, in which all the pixels’ photodiodes operate in photovoltaic mode as opposed to photoconductive. By doing this the camera can toggle between image capture and power capture on each image collecting cycle; with each frame, the camera captures an image and then generates electricity.
When the camera is not capturing images, it can be used solely as an energy-harvesting device, and that’s where the potential for other self-powering devices—such as watches and phones—comes in. As Nayar explains “We are in the middle of a digital imaging revolution… I think we have just seen the tip of the iceberg. Digital imaging is expected to enable many emerging fields including wearable devices, sensor networks, smart environments, personalized medicine, and the Internet of Things. A camera that can function as an untethered device forever—without any external power supply—would be incredibly useful.”
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