Researchers at Columbia Engineering have made a prototype video camera which is world’s first fully self-powered camera. This camera can take one picture per second in a well-lit indoor space for an infinite time. This research team led by T.C. Chang and Shree K. Nayar designed a pixel that not only measures the incident light but also produced electricity with this incident light. This simple pixel circuit’s photodiodes perform this task.
This could be a revolutionary step towards creating cheap standalone cameras of small size which could be a integrated easily in Internet of Things devices and sensor networks. Shree Nayar, the professor at Columbia University tells IEEE: “For these applications to be successful, the camera has to be more or less standalone.”
He adds, “You want to be able to deploy them and forget about them while they continue to function. And you want them to be really small and really cheap. One obvious way to make a self-powered camera is to attach a solar panel to a camera, but that’s not the most viable solution in terms of cost and size.”
The digital cameras and solar panels are different devices, but they are made using the same components. In a digital camera, there’s an image sensor with millions of pixels. In a pixel, there is a photodiode that generates electricity. Using this mechanism, pixels measure the light intensity. The very same photodiode is used in solar panels to generate electric current.
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The pixel is designed using two simple transistors. In the process of capturing image pixels are used to record the image and then charge the sensor power supply by harvesting energy. Thus, the image performs alternate functions of image capture and power generation modes. This could be used in phones and the energy used to power camera could be utilized to run the phone.
Further, image sensor could be connected to a rechargeable battery and energy could be stored. However, this camera is fully self-powered and used a capacitor to store the energy.
This looks like a small step towards a next-gen cameras that can work for a very long time and ideally- forever without any power source.
With inputs from https://spectrum.ieee.org/