Researchers at Columbia Engineering have invented the world’s first prototype video camera that is fully self-powered. It is capable of producing one image per second of a well-lit, indoor scene, potentially continuing to take images forever. The team, led by Shree K. Nayar (T.C. Chang Professor of Computer Science at Columbia Engineering) and funded by the Office of Naval Research, is presenting its achievement at the International Conference on Computational Photography at Rice University in Houston, April 24th-26th.
“We are in the middle of a digital imaging revolution,” explained Nayar, who leads the Computer Vision Laboratory at Columbia Engineering, “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 [may] function as an untethered device forever–without any external power supply—[might] be incredibly useful.” Around two billion cameras were sold worldwide last year, so the impact of such research might have far-reaching influences and benefits. Initially, the camera needs to be powered-up with an external power source. However, following that, it is on its own.
The innovative design was apparently conceived by bringing together two separate technologies: solar panels and digital cameras – the former converts light into electrical energy, the other measures light. Interestingly, both are constructed from essentially the same components. Digital cameras contain image sensor chips packed with millions of pixels. The key part of a pixel is a semiconductor device called a photodiode, which transduces light energy into an electric current. Therefore, the photodiode allows each pixel to measure the intensity of light falling on it. Similarly, photodiodes are used in solar panels to convert light to electricity. In scientific terminology, the photodiode is used in photoconductive mode in digital cameras and photovoltaic mode in solar panels.
Nayar built the self-powered camera’s image sensor with 30 by 40 pixels from ‘off-the-shelf’ parts. In Nayar’s camera, the photodiodes in each picture are operated in the photovoltaic mode. When it is recording, the pixels initially record and read out the image, then switch to harvest the light energy and charge the sensor’s power supply. Notably, if the camera is unused, the electricity it produces may be used to charge other electronic devices, such as a mobile phone or a tablet.
The video above demonstrates the camera’s ability to capture footage. The image may appear grainy and low-resolution. However, the quality is sufficient to be set up in exotic environments like the jungle, in order to monitor elusive wildlife or even be used on another planet.
“A few different designs for image sensors that [may] harvest energy have been proposed in the past. However, our prototype is the first demonstration of a fully self-powered video camera,” Nayar continues. “And, even though we’ve used off-the-shelf components to demonstrate our design, our sensor architecture easily lends itself to a compact solid-state imaging chip. We believe our results are a significant step forward in developing an entirely new generation of cameras that aim to function for a very long duration – ideally, forever – without being externally powered.”
Nayar reportedly believes that the next step in its development may be to produce a self-powered, solid-state image sensor with many more pixels – a standalone camera that might capture high quality film anywhere. The technology might also be implemented to reduce the power consumption of other electronic devices such as smartphones and laptops.
How might this technology productively be used to power consumer electronics?