Re: randomness

For a cheap truly random number generator, bias a diode near the switch voltage (around .7V for silicon, if my hazy memory serves.) Take the result through an A/D converter. Should be Gaussian (or Poisson, I forget); you could generate a good approximation to a uniform distribution by inverting the source function (see e.g. Knuth, "Seminumerical Algorithms" for an algorithm for producing Gaussian variates from a pair of numbers drawn from a uniform distribution.)