A camera that is able to power itself from the light that it gathers for pictures has been created by researchers at Columbia University. The camera could, in theory, run forever, taking pictures for eternity.
“We are in the middle of a digital imaging revolution,” says Nayar, who directs the Computer Vision Laboratory at Columbia Engineering. He notes that in the last year alone, approximately two billion cameras of various types were sold worldwide. “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.”
A leading researcher in computational imaging, Nayar 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 enabling device in a pixel is the photodiode, which produces an electric current when exposed to light. This mechanism enables each pixel to measure the intensity of light falling on it. The same photodiode is also used in solar panels to convert incident light to electric power. The photodiode in a camera pixel is used in the photoconductive mode, while in a solar cell it is used in the photovoltaic model.
Nayar, working with research engineer Daniel Sims BS’14 and consultant Mikhail Fridberg of ADSP Consulting, used off-the-shelf components to fabricate an image sensor with 30x40 pixels. In his prototype camera, which is housed in a 3D printed body, each pixel’s photodiode is always operated in the photovoltaic mode.
The pixel design is very simple, and uses just two transistors. During each image capture cycle, the pixels are used first to record and read out the image and then to harvest energy and charge the sensor’s power supply—the image sensor continuously toggles between image capture and power harvesting modes. When the camera is not used to capture images, it can be used to generate power for other devices, such as a phone or a watch.
A bright light seared in to being, vanished; Chuck, blinded, peered and then saw, standing in the center of the room with a camera in his hands, a man he recognized. Recognized and disliked.
"Hello, Chuck," Bob Alfson said... "This film I'm using - I'm sure you've run across it at CIA; it's expensive, but helpful." He explained to both Chuck and Joan. "I've just taken an Agfom potent-shot. Does that strike a chord? What I have in this camera is not a record of what you did just now but what will go on here in the next half hour..."
(Read more about the Agfom potent shot film)