A dice is essentially just a special display for numbers from 1 to 6.
Why is a real dice a random number generator? If your hand would have perfect precision mechanics and you could control speed and position exactly then a real dice would probably be deterministic. In other words the one tossing the dice is the one introducing the randomness.
If you look at the code for our electronic dice then you will see that it is just a counter. It counts up while you press a button.
The E-dice is a simple but useful AVR starter project.