Ring shaped magnet opens electronically locked doors

Barry Wels says:

"A magnetic ring (called the ring of the devil) opens some electronic (and electromechanical) locks. Technical details on how this ring works, as well as a video of an opening of an electronic lock can be found at the link below."

The ‘ring of the devil’ is capable of attacking this kind of electronic motor lock on two ways.

Scenario 1: An electronic motor is nothing more then a metal part on an axe that turns because of a changing magnetic field. Turning electro magnets on and off will generate a pulling force on the metal part, making it rotate. The ring does the same thing. By turning the ring, the metal part in the electro motor starts turning, opening the lock. As Rop suggested in the comments of the previous posting, a bunch of bigger magnets and maybe a high-speed drill can amplify this effect some more.

Scenario 2: A dynamo is nothing more then a coil charged by a changing magnetic field. So any coil in the lock will start generating current when a magnetic field is rotating around it. If the coil is in the path of the electro motor, it might generate enough current for the motor to start turning.

Currently we are testing with this magnetic ring. Jord Knaap and Han Fey already found one other electro/mechanical lock that seems to open under some conditions with this technique. As with all problems we personally discover, we are first going to notify the manufacturer to give them some time to analyze the problem. But with the ‘devils ring’ out on the free market it will probably be a matter of day’s/weeks before other people will find (and report) locks that are vulnerable to it.




  1. Someone should try using an EasAlign driver to achieve the same. I saw it on This Old House some time ago and it came to mind at the mention of spinning magnets on a drill, which is essentially what the driver bit is.

  2. Might you also be able to fry the electronic lock by causing a large electrical surge off the solenoid? Would a Faraday cage block the magnetic field?

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