Quantum Random Number Generator Created Using A Smartphone Camera� — The Physics arXiv Blog — Medium

Quantum Random Number Generator Created Using A Smartphone Camera� — The Physics arXiv Blog — Medium:  It’s straightforward to calculate the average number of electrons this process should produce, given the probabilistic nature of photon emission. But the actual number of electrons should differ by a number that is random. That produces a single random digit. And since a light-sensitive array consists of many pixels working in parallel, it is possible to generate a large quantity of random digits from each image...

So the process of generating random numbers consists of pointing the camera at a green LED that evenly illuminates all the pixels and pressing the shutter button. A simple program then extracts the random digits.