A new prototype video camera is fully self-powered and can produce an image each second, indefinitely, of a well-lit indoor scene. Columbia University researchers designed a pixel that can not only measure incident light but also convert the incident light into electric power.

The simple pixel design uses two transistors. During each image capture cycle, the pixels first record and read out the image, and then 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 generate power for other devices, such as a phone or a watch.

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