I prefer using a pseudo-random sequence.  There's no way to cheat with a
Geiger counter randomizing everything!


> If the users would accept it, a microcontroller could eliminate the
> balls, and make the whole thing a non-problem.  Although I've been
> flamed before for suggesting this, an alpha radiation source and
> detector enclosed in a metal box, would give you a provably random
> time between detected particles, and all you'd need then is a counter
> spinning away to say which "ball" is picked, and a list of previously
> picked "balls" to tell the randomizer to "pick again" when it comes up
> with the same number in a given set.  Alpha emitters (like from a
> smoke detector) can't penetrate even a single sheet of paper, so I
> can't understand the very vocal objections I've seen to this approach.
> AFAIK, radioactive decay is still provably random, or at least very
> unlikely to be influenced by anything in the average bingo hall.
> Alpha particles are helium atoms with no electrons.