" If we can't predict it, it MIGHT AS WELL BE RANDOM, but that's another story. "
1, 5, 5, 1, 9, 6
Do you think the above sequence of numbers is random or not?
" I define true randomness to mean that if a system is given an input, the output is not set (INDEPENDENT of human consciousness.) "
That is not the correct definition of randomness. Randomness is an attribute of a set of numbers, it has nothing to do with physical entities. Sets of numbers and their attributes are not real, they only exist in your imagination. You can't have a random set of numbers without a conscious human being thinking about them.
" Personally I think free will is just an illusion "
It's not an illusion as much as it is an ill-defined concept.
" My point is, is that true free will is impossible: our actions are either predetermined or random at a fundamental scale. "
Try this thought experiment:
Imagine a computer which is capable of reading the full contents of your brain and telling you what your next action will be. Can you defeat the computer to prove to yourself that you really have free will? Of course you can so what does that mean? It means no such computer can possibly exist. The 'predetermined' possibility is already eliminated.
What about randomness? Let's go back to our computer; the information about your next action does exist, after all eventually the action happens and your choice becomes known. So where is the information about your actions which the computer can't possibly access? In the future!
So free will is really the act of creating actualities out of possibilities, the concrete out of the abstract, something out of nothing. It's not an illusion, just a difficult concept to understand.
(oops, I did it again...)