Easy button code lock

since i saw the other examples, i thought i'd add another code lock setup of my own. i put it together quickly and it's not pretty, but it works.

with my simple 9 button setup, the door cannot be opened unless all of the correct buttons, but NONE of the incorrect buttons, have been pressed. with this setup, it's virtually impossible to open the door without first knowing the code.

i left the "heart" of the locking system in plain view so you can see what happens when you push each button, and easily understand how it works. when the beam hits the red disk (which is a shootable bu