I'm lost and need your help!

Discussion in 'The Projects Forum' started by SensualLettuce, Dec 2, 2013.

  1. SensualLettuce

    Thread Starter New Member

    Dec 2, 2013
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    Hello,

    Thank you for taking the time for reading this. I've been searching all over the internet for help and I'm a little lost. I'm trying to construct a James Bond style hidden room in my house. And I need advice for how to automate the entrance. I have never wired any motor before, not have no clue what I need to use, but I'm a very quick learner and very good with figuring things out. However with that said, I need things simplified. The door is a hinged book case, and I want to be able to open the door by tilting a book. I was thinking the easiest method to have the door open would be to have a wheel at the bottom connected to a motor to swing the door open. I want it to be able to stop when fully open, and have it automatically shut, along with a secondary control to open the door from inside the room. It's purely for esthetics, and not to be used as a "panic room", so security isn't an issue. My question for all of you is how on earth do I pull this off? What is the best motor to use? How would I supply power to operate the door? How would I reverse the direction of the motor? How would I get the motor to stop when it's open? How would I control it by the book? And is this even a remotely realistic endeavor?

    Thank you so much for your time
    -Kate
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    There is some mechanical engineering required as well as electrical.
    DC motor either on the roller idea or a linear actuator, a proximity switch in the B.C. with a small magnet buried in the cover of the book.
    If a motor is used on the door, use rubber sheathed flex cable to cross the hinge point.
    The motor is reversed by polarity reversal.
    Not a trivial project.
    Max.
     
  3. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    It's not a trivial project, like Max said, but it's not impossible if you really want to do it.

    The important part are that the DC motor has gearing so it can easily move the hidden door, and it needs safety or limit switches, so the motor stops when the door has been opened or closed fully.

    Then you need the hidden switch in the book etc, and the rest is just a DC power supply to operate the motor and some wiring between all the switches and motor and power supply. :)
     
  4. inwo

    Well-Known Member

    Nov 7, 2013
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    There are many commercial openers available. Look one over next time you go into a store with an automatic opener.

    As for DIY the wheel sound safest if not over powered. And it can take load off the hinges.
    A worm-gear box or linear actuator can be powerful enough to break things.

    I have a full size stair case that comes down from the ceiling. Uses a worm-gear drive. Has all kinds of fail-safe switches and is current limited by the pwm controller. Yet I hold my breath every time wife goes into the attic.

    If you can get the mechanics working, the electronics and switches are easy. There will be plenty of suggestions on here.
     
  5. Dr.killjoy

    Well-Known Member

    Apr 28, 2013
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    You want things simply but your plan is very complex .. Why don't you start with something simply and work from there... Also remember to make sure it works properly with no failures. Otherwise if you close it and something fails then how are you going to get in or you going to have some back up device ???
     
  6. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    If the hinges are robust and low friction and the hinge line is truly vertical then the force required to open/close the door could be within the capabilities of a car screen-wiper mechanism plus a bit of reduction gearing. Worth a trip to the breaker's yard?
     
  7. inwo

    Well-Known Member

    Nov 7, 2013
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  8. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Good point, I could imagine a very strange obituary if the hidden room is ever found - especially strange if the OP's handle is indicative of her actions (or plans).
     
  9. wayneh

    Expert

    Sep 9, 2010
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    If this was my project, I would lean very heavily on an existing commercial design and modify it only as needed. Maybe you can find a used door somewhere to scavenge for parts.
     
  10. SensualLettuce

    Thread Starter New Member

    Dec 2, 2013
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    Thank you all so very much for all of the help! I'm grateful to all of you. I was looking into commercial opener, however the load specifications don't work. So I'm doing the diy method. I've narrowed it down it a geared, reversible ac motor, a USB audrino, and a few proximity switches as well as a on-off-on switch for inside the room. I just hope all goes well.
     
  11. Dr.killjoy

    Well-Known Member

    Apr 28, 2013
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    How about staying away from electronics and sticking with more mechanical ???
    Will you have a back up in case of no power or the system crashes ???
     
  12. SensualLettuce

    Thread Starter New Member

    Dec 2, 2013
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    The door is going to be able to just be pushed open as well, the automated part is simply because I thought it would be awesome.
     
  13. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I would have thought that a AC motor would have been low on the list, especially if it is a 1ph induction motor and you need to control the rpm?
    And I would not have though it required the 'Brains' of an arduino?
    Max.
     
  14. inwo

    Well-Known Member

    Nov 7, 2013
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    That's the information he is looking for.
    He won't know if it isn't suggested.

    A brushed dc motor is a good choice for controlling speed and torque.
    Can be overloaded significantly for short periods.

    What are you thinking for mechanics? Chain, belt, drive wheel, direct torque on axle?

    I used a 90 volt dc motor/worm-gear box, and a cheap $100 industrial regenerative control.

    Control circuits are NOT isolated from control, but can be safely fused, and the whole system can be on a gfi.

    Switching, speed, and direction can be done with micro switches and a couple resistors.
    It's really the only component you need

    For example when my staircase is near closed, it hits a nc microswitch adding resistance in the one direction slowing motor, and reducing power until it stalls while "sealing" home.
     
  15. inwo

    Well-Known Member

    Nov 7, 2013
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    Not a bad idea.

    If I was a m engineer. I'd be thinking counter weight, Latches, Balance.
     
  16. tubeguy

    Well-Known Member

    Nov 3, 2012
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    shortbus likes this.
  17. inwo

    Well-Known Member

    Nov 7, 2013
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    Like balanced to close closed and "pulled" open?

    Made an outboard motor lift like that once. It had a linkage that would lift motor, but motor could swing up by itself also.
     
  18. inwo

    Well-Known Member

    Nov 7, 2013
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    Ingenious, wish it would show manually opening the door. I can't visualize it yet.:confused:

    ps.
    I get it. The blue part can pull away from the red.
     
  19. tubeguy

    Well-Known Member

    Nov 3, 2012
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    Yeah, It's a neat mechanism. But it will take some DIY skill to fabricate.

    BTW. A great supplier for mechanical goodies is McMaster-Carr
     
  20. MaxHeadRoom

    Expert

    Jul 18, 2013
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    With a name like Kate sounds like a she not a he?

    I am leaning toward the linear actuator with a hinged arm that fold up on itself.
    There are really cheap DC controllers on ebay, even the SCR type by KB/Baldor etc.
    Max.
     
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