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"Cracks" Garage Door codes

Most Remote Control Garage Door openers come with a series of switches that a user flips up or down and makes consistent with the Garage Door opener unit itself. Presumably the combination of switches in the RC unit broadcasts a single signal which is received by the Door Unit inside the house and opens the garage door.

What about a Remote Control unit that tries all possible combinations over a very short time period and thereby opens the garage door you are standing in front of?

One would have to decrease the range of the frequencies emitted (to maybe 10-20 yards) because you wouldn't want to be opening everyone's garage door within 75 yards of the signals broadcast.
-- joetcochran, Sep 19 2005

DIY http://www.ee.washi...ircuits/garage.html
[half, Sep 19 2005]

Which it has been. (link)

I'm not sure, but I'd imagine that "Most Remote Control Garage Door openers..." may be an overstatement today. It looks to me like the rolling code systems are becoming the norm.
-- half, Sep 19 2005


Horrible, yes. But possible. Makes me want to go out and replace my garage door. Especially considering this idea appears to be baked already.
-- joetcochran, Sep 19 2005


Won't work. These days, there is a good chance that Garage door openers use "rolling codes" just like car locks. This refers to the code being changed each time it is used. The receiver uses an algorithm or a code table to look up the next code. Even if you sit and record/scan the code the owner just used, it won't work if you re-transmit it. They also won't accept high speed attempts at breaking of the code either. Sorry
-- BritUSA, Sep 19 2005


Yep, it's baked, they were popular in the 90s with criminals, who also simply recorded the code transmitted by someone as they closed the door on their way out, and playing it back later.

A 12 switch opener (The best there is, that I know of,) would have 4096 possible combinations. Assuming two seconds to flip a switch and hit the button, a dedicated burglar could use themselves as a manual scanner, and get the door open in less than three hours.

Some of the more recently made garage door openers to still use the multiple switch coding systems were designed to stop accepting codes after so many tries one after another, but for anything made before about 1987, these sort of devices work painfully well.
-- ye_river_xiv, Jul 13 2006



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