Zenerglass

The Zenerglass is a simple implementation of a reverse biased Zener diode entropy source. The diode creates avalanche noise and feeds the unamplified but buffered signal into the analogue to digital converter within an Arduino Uno. It’s super compact, standing only 280mm high and operates on a lowly (external) 12V. It generates 175kbps of entropy via it’s Ethernet connection. Reiterating: it’s an entropy source, not a fully fledged true random number generator.

It also has pretty lights that indicate when someone accesses the device…