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Secret Bookcase Door Switch - Help?

  1. Dec 1, 2013 #1
    Hey folks -

    Question. I'm working on a secret door disguised as a bookcase and I'm looking for some help from a curious and knowledgeable electrical engineer about a clever way to make the lock open.

    The desired effect is for the opener to touch two brass busts on the bookshelf simultaneously and the deadbolt will unlock and the bookshelf/door will open.

    I'm wondering if these two concepts can be combined:

    1. A stick that shows that the human body is a conductor (right word?).

    2. A new type of deadbolt that (if you have the bluetooth fob) opens by touching the deadbolt rose.

    Is it possible to combine them or will the power required to work the lock shock/kill the person who acts to complete the circuit?

    My plan was to cut the wire that connects the deadbolt rose to the main servo and then run that to both busts and then run another wire from either bust directly to the deadbolt rose to simulate the touching. Then, when somebody touches both busts, the circuit will be complete and the lock will open?

    Is this a good or bad idea? Is there a simpler method? Don't say use a key. ;)

    Last edited by a moderator: May 6, 2017
  2. jcsd
  3. Dec 1, 2013 #2


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    Staff: Mentor

    No problem to combine both ideas, but not by passing the current through the body. More like shorting brass busts should trigger the switch opening the bolt.
  4. Dec 1, 2013 #3
    Great! Can you explain what that means and how I might set it up?


  5. Dec 3, 2013 #4


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    Gold Member

    You might want to use two capacitive touch sensors, so that both must be energized simultaneously, for instance, to unlock your secret compartment.

    MPR121 Capacitive Touch Sensor Breakout Board

    A veritable shopping list of suppliers:
    http://www.mouser.com/Sensors/Capacitive-Touch-Sensors/_/N-1b8oy [Broken]
    Last edited by a moderator: May 6, 2017
  6. Dec 13, 2013 #5


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    Staff: Mentor

    What happens when the house power fails, or your battery goes dead?

    IMO, it's best to use mechanical interlocks for things like this. Heck, just make a flush button near the back of one of the shelves and put books in front of it. Especially if you put it on the underside of the 2nd-to-bottom shelf at the back, it will be virtually impossible to find.

    What'cha going to put in your hidden closet? :smile:
  7. Nov 14, 2014 #6


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    Gold Member

    Hey, Berkeman, isn't it obvious: That's where he is going to hide the bodies!!
  8. Nov 14, 2014 #7


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    Gold Member

    My Christmas tree lights have a brass ornament that hangs on the tree. You touch it to turn the lights on and off. You could buy two of those and bust them open.
  9. Nov 24, 2014 #8
    I agree with Berkeman

    seems a bit extreme for a no security lock. be easier to use a mechanical switch like pushing in the kicker with your toe unlatches the unit to swing or slide out which would solve the no power issue. the other way could be use the same finger print swipe's as laptops one on each bust which means only registered users can actually unlock the door.
  10. Nov 25, 2014 #9
    Temperature sensors in the busts that measure a rise in temperature if the busts are held.
  11. Nov 25, 2014 #10


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    Gold Member

    Oh, hell. Just get an RFID chip implanted in your arm and be done with it.
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