You can see a video of the Cloudflare lava wall by [Tom Scott], below. If you don’t need a random number generator, maybe you could use a spectrum analyzer. Thanks to [Ptkwilliams] for the tip.

Admittedly, the SB42 Random Number Generator built by [Simon Boak] isn’t exactly something you’d be using for cryptography. The method used to generate the digits, a pair of 555 timers sending ...