Using a relay to open and close a gate

Discussion in 'The Projects Forum' started by mmclary, Mar 31, 2016.

  1. mmclary

    Thread Starter New Member

    Mar 31, 2016
    3
    0
    I installed a gate opener (Aleko) which can be controlled by a non-powered push button. I also purchased a video intercom that has an unlock feature (NO COM NC). I would like to send the unlock signal to open the gate. The NO and NC send 12V signals and cannot be hooked up directly to gate opener via the O/S/C connect (same one used by the non-powered push button) because the 12V would fry the board.

    I believe a 12V relay work allow me to use the NO or NC unlock feature to power a switch that will work similar to the non-powered push button.

    What type of relay did I need to buy? Am I going down the right path?

    Thank you
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,137
    3,054
    An automotive relay would be easy to find and would be fine for the 12V operation.

    A few questions:
    What's a "non-powered" push button? Is this like a door remote?
    The relay you choose will require a current (usually given in milliamps, mA) to operate. Your intercom has a max current rating on its output. You want the intercom to be rated for more than the relay requires. Can you tell what these ratings are?
    Can you describe the gate "O/S/C connect" in more detail? It's possible you don't need a relay at all, you may just need to condition the intercom output to match up to the gate input.
     
  3. mmclary

    Thread Starter New Member

    Mar 31, 2016
    3
    0
    Thank you for responding! Really thank you....

    Answers below:

    What's a "non-powered" push button? Is this like a door remote? (please see product via link...http://www.alekogates.com/ALEKO-LM147-Push-Button-for-any-GateOpener-p/lm147-ag.htm)

    Screen Shot 2016-03-31 at 10.49.57 PM.png



    The relay you choose will require a current (usually given in milliamps, mA) to operate. Your intercom has a max current rating on its output. You want the intercom to be rated for more than the relay requires. Can you tell what these ratings are? 12V 2A


    Can you describe the gate "O/S/C connect" in more detail?

    This is all I have for you..."Push Button or wired keypad (optional) The red or blue wire should be inserted into either O/S/C terminal, the white wire into the other one." Screen Shot 2016-03-31 at 11.03.24 PM.png
     
  4. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,998
    745
    I would say that the video intercom relay can be altered, try looking at the Com terminal, and remove the link to its supply, that will make it a voltage free contacts. Otherwise its using a 12v relay powered from the video unit, you could parallel the coils up, or use the No and battery negative supplies.
     
    Last edited: Apr 1, 2016
  5. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,801
    1,105
    Is the push-button dual purpose; one push for 'open', another push for 'close'?
     
  6. wayneh

    Expert

    Sep 9, 2010
    12,137
    3,054
    You can do this without a relay, but if you already have one in your junk drawer, you're done.
     
  7. mmclary

    Thread Starter New Member

    Mar 31, 2016
    3
    0
    Great! Thank you everyone. Wayneh - how do I do this without a relay?
     
  8. wayneh

    Expert

    Sep 9, 2010
    12,137
    3,054
    As double D said in #4, you can eliminate the connection of common to the intercom's power supply. When the intercom's relay closes the circuit, it will simulate a manual push button being pressed.

    You might not even have to alter the intercom, but more testing would be needed. The push button might normally connect one of the gate inputs to ground. And you might be able to connect the commons of both devices. If that's all true, then your intercom is already able to do the job. But again, you'd need to confirm what the switch is doing and whether you can connect the two grounds without current flowing from one power supply to the other.
     
    Dodgydave likes this.
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