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Just a quick update on my Random Number Generator project. I have finally managed to get a random white noise output from the circuit using transistors, instead of a zener diode.
The principle is the same as the previous circuits (reverse breakdown) but the transistors seemed to work better as noise sources. This is probably because zener diodes are designed to operate in reverse breakdown mode, and to produce as little noise as possible (it is generally undesirable), while transistors are not designed to be operated in this mode and will therefore produce more noise.
I also used an opamp to amplfy the signal, which should make it easier to capture the noise on the arduino. I have yet to properly test this with the arduino chip, but I am somewhat confident I will get some good results.
I may not be able to get true random numbers directly from the RNG, I may instead use the RNG to seed a psuedo random number generator. A pseudo random generator seeded with true random values should be a lot more effective than a pseudo RNG on it's own, while not requiring particularly advanced hardware in the RNG.
I did have some problems with the waveform being "cut" after the amplifier stage as seen here:
But this turned out to be incorrect placement of my oscilloscope probes.
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