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Using Radio-Controlled Magnetic Copper Wires to Unlock Door
Last Post 08 Apr 2014 10:24 PM by Mike McGregor. 2 Replies.
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Bill M
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Posts:1

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29 Jan 2014 08:41 AM
    Goal: I don't want to open my door by inserting a key; instead, I want to unlock it remotely/wirelessly from the outside.

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    Pictures of my Mortise lockset:

    http://i40.tinypic.com/5pftxi.jpg

    http://i39.tinypic.com/11ghq9l.jpg

    http://i41.tinypic.com/30kzsyc.jpg

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    Description: The first picture is a full shot of the interior knob. The second is a close up of the space between the lock buttons and the door frame (less than the thickness of a penny). The third is a shot of the lock buttons from the side. In this picture, there are two lock buttons: one for keeping the lock unlocked (bottom) and another to keep the lock always locked (top). Here, it's currently locked. Top one is depressed; bottom one is raised. They are connected, so if one goes up, the other goes down.
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    Notes: I have already considered electromagnet solenoids, replacing the locks, adding magnetic latches, and so on. I can't do anything to physically modify the current lockset and door.
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    Current design: My idea (so far) is to place magnetic copper wire into the top lock button. To hold it in place, I may use some sort of non-conductive clay with the radio-controlled power source taped to the interior door. What I'm hoping for is the magnetic copper wire will attract the metal lock button and raise it out of the unlock position.
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    Questions and concerns: I'm not sure how much copper I need, which direction the magnetic field will pull on the lock button, what type of remote-controlled power source would be most appropriate, how much power (or magnetic force) would be needed to pull the lock button, and what kind of clay or tape I should use to hold everything together without getting shocked and endangering my neighbors. I also don't know where to buy all of these items online. Could someone please guide me in completing this project?
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    Please critically analyze the faults of my project outline, answer all of my concerns (and add anything else necessary), and provide links to the materials you specify. I would really like to get this done as soon as possible.
    Mike McGregor
    New Member
    New Member
    Posts:22

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    08 Apr 2014 10:21 PM
    You need to find out how much force you require the solenoid to pull. Use a newton meter for this purpose (or one of those electronic scales you hang your luggage from before going to the airport, to pull against the lock).
    The solenoid must be secured with something much more substantial than clay or blu-tac. Newton's third law tells you than whatever force the solenoid applies to the lock, will be the same force that attempts to rip the solenoid away from it's mounting.
    Don't use a home-made solenoid from scrap wire. You have heard of the principle of not reinventing the wheel? Commercial solenoids exist that are encased in epoxy resin. This will prevent electric shocks. The force the solenoid pulls will be stated by the manufacturer.
    Be aware (for fuse design purposes) that the initial surge of current will be higher than the standing current. The standing current settles lower than the initial surge because the bolt is attracted into the hollow core of the solenoid. By mutual induction, opposing currents are established that reduce the resultant. If your design does not have the lock bolt entering the solenoid core, then the solenoid may burn out, because the intial surge never gets reduced.
    Mike McGregor
    New Member
    New Member
    Posts:22

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    08 Apr 2014 10:24 PM
    Additionally,
    any direction of magnetic field will pull the lock. Ferous metals are attracted to North poles and South poles. Repulsion only happens with two magents.
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