New Self-Powered Cameras Will Mean Never Having A Dead Battery

Have you ever found yourself faced with a spontaneous moment of beauty only to pull out your camera and find the battery dead? Or maybe you've embarked on a long-distance back-packing trip which is endlessly scenic, but provides limited access to power outlets for recharging. Scientists have now got you covered as they unveil a new means of producing self-powered cameras.

Self-powered camera: the pixels of this camera prototype not only measure incoming light, they also convert it to electrical power. Image from Columbia's Computer Vision Laboratory.Self-powered camera: the pixels of this camera prototype not only measure incoming light, they also convert it to electrical power. Image from Columbia's Computer Vision Laboratory.

While it sounds fanciful, the idea behind a self-powering camera is actually quite basic and it is somewhat of a wonder that it has taken this long for the development of a prototype. We already know light is capable of being used in the generation of power -- see: solar cells -- and each pixel of a camera's lens is simply a light-measuring device. By combining the light-measuring property of the pixel with the technology to then convert the incident light into electrical power, a self-powered camera is realized. This strategy is an improvement over simply incorporating a solar cell into the camera as it promises to be less expensive and more compact.

The Columbia University researchers accomplished this by employing pre-made photovoltaic cells as camera pixels. The cells are already produced such that they convert light to electricity, so the only task in this study was to evaluate their function as light sensors. In order to generate an image, an array of 30 x 40 of these pixels was fabricated to act as a prototype camera. The researchers found that in a well-lit indoor scene, the camera could generate one image per second indefinitely. Not only does it take photographs, in these sufficiently well-lit areas, the camera can even record videos. This is particularly valuable given the drain that videography often has on device battery life.

The battery-less camera captures a still-life image: images from "Towards Self-Powered Cameras,"  S. K. Nayar, D. C. Sims, M. Fridberg,  Proceeding of the International Conference on Computational Photography (ICCP),  pp.1-10, Apr, 2015.The battery-less camera captures a still-life image: images from "Towards Self-Powered Cameras," S. K. Nayar, D. C. Sims, M. Fridberg, Proceeding of the International Conference on Computational Photography (ICCP), pp.1-10, Apr, 2015.


But what happens in lower light situations? The power obtainable through the photovoltaic pixels would in this case be considerably less. To manage this, the scientists developed a controlling program such that the frame rate decreases from one image per second as a function of lowering of the incident light. Essentially, the camera will only take an image when it can energetically “afford” to do so, ensuring indefinite operation.

The current prototype, which was built from off-the-shelf parts, has pixels about 1000 times larger than those in a typical modern digital camera, making this model relatively unwieldy. However, if there’s one thing that electrical engineers have mastered, it’s the miniaturization of electronic components. Just look at the Moore’s law-described evolution of the transistor! With this in mind , it should only be a matter of time before the frustration of a dead camera battery is a thing of the past.