Researchers at Columbia University may have solved the age-old dying battery problem by developing a fully self-powered camera which converts light into electrical energy.
The researchers started by designing a pixel circuit where the photodiode first measured the incident light level, then converted the incident light into electrical energy which then powers a simple camera. Before you get too excited though, the camera did have to get a boost of sorts to start with. Using a supercap instead of a battery, the supercap is initially charged to start the camera but once charged it recharges itself using the energy that is harvested from the pixels. As long as the scene is a certain brightness, in this case around 300 lux (lumens per square meter), the camera can take an image per second indefinitely.
The power harvesting image sensor array is a grid of 30×40 photodiodes which includes a microcontroller. The back side of the sensor houses the harvest switches and power supply which recharges the supercap. The image below shows the setup used to evaluate the camera and researchers adjusted the brightness of the scene with a dimmer and found that the supercap stabilized around 3V at 200 lux which was above the 2.5V minimum required for the camera to to function. A value of 200 lux isn’t much and represents a dim to dark indoor setting, which shows that the camera doesn’t need that much light to continue to operate. For comparison, a typical overcast day is between 1,000-2,000 lux.
A sample video below shows just how rudimentary the camera is, but it’s a start for sure.
It’ll be interesting to see where this tech goes, let us know what you think of the research in the comments below or on Google+, Twitter, or Facebook.Source: Columbia University
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