system
Given the following post, respond as if you're commenting on Reddit:
human
[General SciFi] How does one "hack" a door?

You've seen it in plenty of games and movies, with everything from recrossing a few wires to ripping the keypad off with a knife and shoving a device in it or even a wire to let them try and manually do it. My question is, what are they really trying to do? What would the steps be?
gpt
There are two... maybe three methods of doing this, not counting the external device variant.

The first is controlling the mechanisms that open and close the door. Now, these can be code- or lock-controlled to stop anyone from opening them but by ripping off the panel and directly interfacing with the electronic controls, you're able to directly control the motor that opens and closes the door. it's actually a pretty simple mechanism of a motor which controls if the door opens or closes and this can be controlled by creating a current to go through one way or the other.

The second is actually a safety feature, one that is legally mandated in all modern electronically-closed doors. By destroying the control panel, there's no way to open the door or not in case of a genuine emergency, so OSHA mandates that if a door's control mechanisms aren't functioning properly then the doors *must* be able to self-identify that the controls aren't functional and open themselves up. Now, certain doors are exempt from this, such as those leading into open space in which case the doors will not open until the controls are fixed or those which keep something dangerous inside, such as radioactive materials.

Believe it or not, this is the reason for the Doors mechanic in the original *Five Nights At Freddy's*. As Freddy Fazbear's Pizzeria is legally a private business open to the public then the doors on the security room must follow this function... so if you run out of power then the doors automatically open up because legally it's the safest option (also because that room doesn't have any vents). What the lawmakers didn't take into account was that there would be homicidal robots walking around the restaurant late at night looking to murder the security guards, or that the owners were such cheap bastards that they power the whole place off of a car battery or whatever instead of the mains electricity.