Random, from radioactive decay
A CAJOE Geiger counter, a Raspberry Pi, and a comparison of one gap between decay events with the next. If the first is shorter the bit is a one, if the second is shorter it is a zero, and equal gaps are thrown away.
Nothing here generates a number. The bias cancels by symmetry rather than by correction, which is why the raw stream is worth measuring at all: everything below is that measurement, taken continuously and not smoothed.
The same bits, drawn: the entropy views live on tinymachines.ai, beside the instrument itself.
The source
Asking the Geiger box.