Arduino random number generator using sha1 for hammering in randomness wether we need it or want it.
The calibration routing is from the orignal code and helps deal with things that happen to transistors as they aged. Find a micro-E for an actual explanation that makes sense.
NOTE: If you change the transistor to something with a different reverse bias threshold, the entire thing can either get better or fall apart completely
Instructions for constructing the circuit can be found here: http://robseward.com/misc/RNG2/