General Question

quarkquarkquark's avatar

What effect does a magnet have on an electronic room lock?

Asked by quarkquarkquark (1695points) May 1st, 2009

I’m thinking of the kinds of electronic locks through which you slide a magnetic-stripped card. If a powerful magnet were held to one of these, would it stop working? I’d love to hear the take of engineers or security professionals on this.

Observing members: 0 Composing members: 0

15 Answers

asmonet's avatar

Sounds like you’re trying to get into a hotel room.

I worked in a hotel, we kicked out ten or so guys carrying magnet collections through the halls over my two years of employment.

They never got in.

Not a science or security answer, just an anecdote.

asmonet's avatar

I should add, we also called the police.

Fyrius's avatar

Not an engineer here, either, but I’m pretty sure that magnetic-stripped key cards work because the lock recognizes information stored on the magnetic strip.
Trying to open a magnetic lock with a magnet that just indiscriminately attracts everything would then be a bit like trying to get a combination lock to open by rubbing the numbered disks against a rough surface in random directions.

quarkquarkquark's avatar

I’m not trying to open one; I’m actually wondering, sincerely, whether the lock stops working. I remember accidentally fucking up friends’ TVs or computers with little magnets and I’m wondering if the amount of electronics in one of these locks would be affected to this degree by a magnet. I don’t see how it would open such a lock; it seems plausible that it would break one.

Fyrius's avatar

Ah. Yes, I can imagine it would interfere.
But I suppose I should leave this question to someone more qualified to answer it.

Offero's avatar

The best way to overcome a locking mechanism is mechanically, not electronically. If it is a hotel room handle lock then by law from the inside you should be able to open the lock by lowering the lever. There is a tool you can use that will go under the door(called suprisingly enough) an under the door tool. It loops the handle from the outside of the door and with a wire you can bend the spring gage so that the lever on the inside of the room depresses and the door opens.
As for your original question, any magnet sends out an electric vector of some sort. That is what makes a solenoid engage and disengage as current passes through an electro-magnetic switch. The “Jump” of the current is what causes the movement. Higher the amps the larger the jump. It is possible with a high enough amount of amps to short a resistor or a diode.

quarkquarkquark's avatar

a.k.a. a big magnet?

Offero's avatar

An electro magnet. Not a ferris magnet.

quarkquarkquark's avatar

This is because you’re talking about a dynamic as opposed to a static electromagnetic field?

Offero's avatar

The electric current must be sent as a vector force in order for the damage to be pin point enough to cause any surge across a circuit board. The only way I can see this can happening is by wrapping a coil around the circuit board and electrifying it. Otherwise I do not see how the shielded components of a circuit board can be damaged.

justwannaknow's avatar

When these locks were first developed, these same questions were considered and safe guards put in place to protect the system from standard magnets. Hotels still get upset at people trying. Not out of fear they will work but for the simple reason YOU ARE TRYING to get in.

quarkquarkquark's avatar

I really am not trying. I live in a dorm and got curious about our locks, which are much the same as hotel locks. So I asked Fluther, because that is what Fluther is for.

Bagardbilla's avatar

someone isss about tooooo beeeee surprised tonight

roodypoohman's avatar

Me and several residents at a motel have been robbed and the police want to know how did someone get into the room. I heard from a little bird that the inspection on the swipe log from the door locks were wiped out. That’s why I also think there is a way someone used a magnet to defeat the lock rather than a mechanical way. Any concrete help would be appreciated.

Answer this question




to answer.

This question is in the General Section. Responses must be helpful and on-topic.

Your answer will be saved while you login or join.

Have a question? Ask Fluther!

What do you know more about?
Knowledge Networking @ Fluther