Summary:
A giant redstone combo lock which combines a code set by the owner and a randomly generated code to open an incredibly well placed iron door.

Details:Outside the device has 3 inputs from 0-9 for your personal code used for opening the door.
Another 3 digit code which is randomly generated (also 0-9 for each #) is displayed inside.
These codes can be averaged together to find the correct combination, which when successfully entered using the buttons along the wall (0-9 but going up by 0.5 per button) will open the outstandingly designed iron door.
After a delay the door will close and the system will reset, generating a new 3 digit code and therefore a new combination.
When any digit in the combo is incorrectly entered or the timer (the 2 numbers to the right of the code display counting down from 99) reaches 0 the system also gets reset, which includes the floor opening up and likely emptying the room of all minecrafters.

A few additional things to note are that the combo is order sensitive and does not allow for a correct button to go unpunished when pressed at the wrong time.
Finally, when not "in use" (the button to open the entrance to the device changes it to "in use" and a reset changes it back) all numbered buttons are treated as incorrect and reset the system if pressed.

Many thanks to the youtuber Cubehamster, I used both his redcoder wiring and his adder in this build and they saved me loads of time.
Cubehamster:https://www.youtube.com/user/cubehamster
Redcoder:https://www.youtube.com/watch?v=ct2zp1RRRcU
Adder:https://www.youtube.com/watch?v=7rdoO55rHAw
Other than that and some of the usual looking at the wiki this was all my work and I am quite proud of it, being my only significant build in minecraft :)