Skip to content The quest for true randomness has roots in cryptography and is a rabbit hole that gets surprisingly deep with alarmingly rapidity. Still, the generation of random- enough numbers is a popular hacker project. Part of the appeal is the way these devices strive to incorporate physical phenomena, and in [Joshua Coleman]’s case, his Neon Entropy (Pseudo) Random Number Generator  uses a trio of vintage neon lamps. Neon lamps discharge at rates that vary unpredictably. They’re also pretty to look at. [Joshua] chose neon lamps in part because the discharge rate of an energized lamp is a variable, physical process that makes a good source of entropy. They also have an attractive visual appeal that fits the concept [Joshua] had in mind. Unlike random number generators that kick off by measuring radiation or some other imperceptible thing, it’s possible — at least in a sense — to see this one working.…