Introduction: How to Build a Redstone Passcode Door.
This is a photo of the Redstone circuitry when it is done, though it looks more complicated because the alarm system is an arrow shooters instead of a bell
Step 1: Start by Adding the Front of the Build and the Levers
Step 2: Next Build the Passcode Mechanism
To do this decide which levers go up and which ones go down. My example shows how to do UDUD (up down up down) but you can do what you want. Behind each lever that you want turned off (up) place a repeater facing away from the lever with a one tick delay. For each lever that you want to turn on (down) place a Redstone torch behind the lever. Then run Redstone dust along the torches and repeaters.
Step 3: Make the Confirmation Sequence
In front of the passcode mechanism place a block. Then put a Redstone torch on it.
Run a Redstone wire from the back of the confirmation lever (the lever that is seperate from the others) to a sticky piston that, when activated, pushes a block in front of the Redstone torch. Then put a sticky piston in front of where the first sticky piston pushes its block. On the new sticky piston, place a Redstone block. In front of where the Redstone block gets pushed when activated, place a block with Redstone dust on top of it. Place a Redstone torch on the side facing away from the sticky piston. Finally run a Redstone wire to your door. (My example is a piston door but you can use any door).
Step 4: The Alarm Mechanism
This is optional and advanced, so don’t make this if you aren’t comfortable. Or you could watch the video of me doing this on my YouTube channel, Dumb Things To Do Hi. Anyway, place a sticky piston where the first sticky piston you placed’s block is when the first piston has power. The new piston is also facing the same way as the first piston and has a Redstone block attached to it. Then run a Redstone wire from where the Redstone block you just placed will be when it’s piston is extended up to a NOT gate to make the NOT gate, you need to place a block in the path of the wire, and then run the wire on top of that block and end the wire there. On the other side of the block, place a Redstone torch. Then, from the NOT gate, run a wire to your alarm system. The alarm system is made with two sticky pistons pushing two observers facing each other so that they are in between to bells. Make sure the wire reaches BOTH sticky pistons. Finally build a wire from the wire that comes out of the confirmation lever, and run it into a NOT gate. Then run the wire from the other side of the NOT gate into a sticky pushing a Redstone block that when extended, touches the wire that leads into the alarm system. (Note: make sure that you run the wire into the alarm wire before the alarm wire runs into the NOT gate)
That’s all, and happy building!
P.S if you have any problems, leave a photo and say the problem in the comments.