Bypassing Basic Door Alarms

Here's a basic method for locating, assessing, and bypassing simple magnetic door contact sensors. This method doesn't defeat sensors with multiple reed switches or sensors like the magnasphere. However, different bypass techniques exist for those devices.
If you would like a Hall Effect sensor of your own but don't want to pay $100-200 for a Gauss meter with Hall Effect functionality, I recommend building one using an Arduino: maker.pro/arduino/tutorial/ho.... Don't try to Jerry rig a commercial device like I did--it was a ridiculous waste of time.
Note: My discussion of reed switches was simplified for the sake of brevity. If you are an electronics enthusiast and have a known heart condition, you should probably consult a physician before viewing this video.

[@mr.anonymous298]

Thanks for the video. I was thinking the same that this kind of system can be bypassed easily. Now I will think of an alternative way to ensure the security of my system.

[@ContingencyLabs]

That's what this channel is all about! I hope my video helps you come up with an innovative solution!

[@christopherlacourciere2476]

Where can I find the exact Hall effect sensor circuit you use? Is it commercially available or did you build the one in the video?

[@ContingencyLabs]

I'm embarrassed to admit that I took the laziest (and ugliest) approach. I removed half of the housing of a magnetic polarity tester, disconnected the hall effect sensor from the existing electronics, and reconnected the sensor with much longer wires. This saved me the trouble of finding new housing for the button, LED's, and batteries, but at the cost of it looking horrible. Still, it works!
This was the original tool: a.co/d/ic1b5ol

[@JMLockpicking]

Your a badass...

[@ContingencyLabs]

Ha! Thanks. Alarm bypass is definitely an under-covered topic in publicly accessible media. But knowing that it can be done makes it easier to figure out how it is done.

[@jacob-zl8xy]

Would it still activate if you took out the magnet?

[@ContingencyLabs]

Once the door is open? Yes.

[@catherinegillett7900]

Can you do this through a door

[@ContingencyLabs]

Usually, yes. My model door obviously doesn't fit tightly in its frame so it's not an excellent platform to demonstrate this. However, the point of laminating the sensor is to allow it to fit in between tightly fitting doors and their door frame, like a shim.

[@Amsterdam020gang]

This would not work on rollershutters made of metal ? Or would u need a super strong magnet

[@ContingencyLabs]

This device does not use a magnet of its own. It's a hall effect sensor that detects the polarity of the magnet used in this kind of door contact sensor. I've never tried it on roller shutters but I have tried it on sheet metal doors and have had no trouble. Theoretically, as long as the metal is not magnetized, it should not impede the device's function.

[@Amsterdam020gang]

I order u a sensor and u test ? Haha, also if its not reachable from outside, any other solutions ?

[@paulb8188]

So you were clever to show us how to bypass, why not take the time to show us how to overcome this problem?

[@ContingencyLabs]

There are a ton of ways to mitigate the threat of this kind of bypass. Most of these mitigations just involve using different kinds of alarm hardware, like sensors that use an array of Reed switches as opposed to just one, compression based door sensors, etc. But these also have their own applicable bypass approaches.
So a video that discusses countermeasures can rapidly expand into something that would be very time consuming and expensive for me to make. But I would love to make that kind of content, if I suddenly found myself the beneficiary of a wealthy patron.

[@catherinegillett7900]

I'm appalled that you're showing thieves this...well done...you should feel so proud

[@ContingencyLabs]

You're not the only one who believes that my videos may be doing harm. I can understand why some feel that way. However, I definitely disagree. If you want to hear me discuss this, check out my ethics video.