Researchers from Columbia University’s School of Engineering and Applied Sciences have created the world’s first self-powered camera that can power itself without requiring separate solar panel or any other external power supply.
We are in the middle of a digital imaging revolution. In the last year alone, approximately two billion cameras of various types were sold worldwide. So, there is a huge demand for Self-powered camera, i-e A camera which can work indefinitely without requiring any external power supply. 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.
They have designed a pixel circuit, where the pixel’s photodiode can be used to not only measure the incident light level, but also to convert the incident light into electrical energy. i-e The same photodiode can be used as both camera part and solar cell. This invetion can lead to cameras which can work indefinitely without requiring any external power. At the heart of any digital camera is an image sensor, a chip with millions of pixels.
Photodiode in each pixel 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 mode.
The new pixel design is very simple, and it uses just two transistors and one photodiode. 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.
To make the prototype camera, the research team bought off-the-shelf photodiodes and arranged them in a 30 x 40 array on a printed circuit board. On the back of the board, each photodiode was wired to circuit components based on the new pixel architecture. This sensor array was attached to a microcontroller, an energy harvester circuit, and a supercapacitor.
The device is a step towards tiny, low-cost standalone cameras that could be useful for wearable devices and sensor networks.This new camera could potentially also be used in mobile phones and smart watches, it could harvest energy for the gadgets when it’s not being used to take images or video.
