I've seen a lot of requests for something similar to this so here:
I had an idea for a pseudo random output generator. Basically it is two pulse unreliable pulse generators (as seen in the pictures) hooked up to two piston T-Flip-Flop's. Both of these T-flip-flops connect to an AND gate. The output of the AND gate leads to another AND gate with the Test button acting as the second input. The output of the last gate goes to a simple latch that controls the redstone torch in the test room. The reset button (obviously) resets the latch. The result is a pseudo random contraption. The two T-flip-flops activate there and gate every 5 seconds or so. Because it is random sometimes it fire at 3 seconds, 4 seconds, 6 seconds, or even 7 seconds. The length of the pulse varies as well.
This device would could be used for many different purposes. The first purpose that comes to mind is a lottery of some sort.
Yes I know nothing in Minecraft can be truly random but this is the closest I can get. It has no pattern as far as I can tell. (It might though)
Explanation Shown above.
The Test Room shown below.
By adding more of the pulsers hooked to AND gates you can decrease the probability that the output will be on.
Due to some back-up error I might've lost the original save. For now I uploaded the result of my tutorial video for people to use.
Optionally you can add a pulse shortener to the output of the button to make it harder to get the torch lit up.
Feel free to ask questions and point out flaws. You may have to replace the redstone on top of the pulsers (but you shouldn't have to).
Replies and feedback are appreciated...