Automatic door

Discussion in 'The Projects Forum' started by Wefinish, May 18, 2009.

  1. Wefinish

    Thread Starter New Member

    May 18, 2009
    2
    0
    Problem- Nocturnal predators kill chickens.
    Solution- Lock chicken coop at night.
    Better solution- Build automatically opening and closing coop door.
    I feel like I'm almost there. I have a power antenna from a Cadillac which I will mount upside down. This will close the sliding hatch when it extends down and open it when it retracts. I plan to use a common lamp timer to trigger it twice per day. I will plug my 12V power into this timer. The antenna has limiters built into it, so that it travels the same distance each cycle, and it also trips off its power after a few seconds spent at full extension or retraction.
    My question is- How can I wire this project to reverse the direction of the motor every other cycle?
    Thanks, Tom Matthews
     
  2. Mike2545

    Active Member

    Mar 26, 2009
    116
    3
  3. CDRIVE

    Senior Member

    Jul 1, 2008
    2,223
    99
    It's kind of difficult to say without seeing your setup. The attached schematic shows the typical method of switching polarity of a motor.
     
  4. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    Can you put to sticks out the side of the door? If so, they can toggle a double-pole-double-throw switch. One stick on the bottom of the door would toggle the switch one way when the door is fully open. The other stick would toggle the switch the other way when the door is fully closed.

    Click on this: chickencoop2.png

    With the switch in the position drawn, the upper relay will energize when the timer comes on. This will latch the upper relay, lockout the lower relay, and the motor will turn in one direction. With the switch other than shown, the lower relay will energize when the timer comes on. This will latch the lower relay, lockout the upper relay, and the motor will turn in the other direction.

    The locked-out relay will only be enabled after the timer has cut power - it will be ready for the next cycle.
     
  5. Wefinish

    Thread Starter New Member

    May 18, 2009
    2
    0
    Thanks. That looks like the thing I need. I will try to wrap my non-circuit head around that. Any chance someone could detail the plain english names of these components.
    The 9452-2 I realize is a DPDT
    The K1 351 ?
    And the devices on the right of thingmaker's schematic?
    Again, Thanks
    I know this has been done before as Mike said, but not by me.
    Tom
     
  6. CDRIVE

    Senior Member

    Jul 1, 2008
    2,223
    99
    The rectangles with the diagonal line through them are relay coils K1 & K2. The contacts for K1 & K2 are to the right of the coils. These are DPDT contacts.
     
  7. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    I apologize for my ambiguity. I was in a bit of a rush and did not delete the part numbers. Any old DPST switch will do, and any old pair of DPST relays with 12V coil will do.

    Tonight at home I will re-draw the circuit with colors on the conductors to make it more easily understood by a beginner.
     
  8. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    Sorry for the delay...
    chickencoop2C copy.jpg
     
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