Light for garage door switch

Discussion in 'The Projects Forum' started by Element1, Nov 26, 2013.

  1. Element1

    Thread Starter New Member

    Feb 6, 2010
    8
    0
    I looked on line and here but i must not be searching correctly because i think the solution is simple but i cant figure it out...

    What I'm trying to do is wire a light to a garage door opener switch so it is on all the time. I have 16 VDC going to the switch. I think I need to wire a high resistance light in parallel with the switch so that it limits the current to the opening motor when the switch is open but that doesn't seem right, how can i accomplish this?
     
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,813
    1,105
    Nor can anyone else without more info ;).
    Post a schematic of your door opener wiring.
     
  3. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    The manufacturer's schematic is not likely to help much. Presumably, you have only two wires going to the switch. You have measured the open circuit voltage (switch open) and you read 16Vdc.

    Now make a new measurement: Put your DMM in the Adc mode, and connect it across the switch and read the current that it takes to get the door moving.

    Say that the DMM reads 100mAdc. That would suggest that it safe to connect something across the open switch which draws <10% of that reading, say 10mA, without effecting the normal operation.

    Try it. Use an LED with a series resistor that limits the current 10mA or less. R = (16-Vf)/0.01 ≈ 1.2K. Most modern indicator LEDs will be more than bright enough with 10mA.

    Good news. My garage door operator wall switch has the internal LED with only two wires going to it, so they are doing just what I described.
     
    Element1 likes this.
  4. Element1

    Thread Starter New Member

    Feb 6, 2010
    8
    0
    Attached is what i have, the inner workings of how the light illuminates without triggering the electric motor (when the button is pressed) is what escapes me.
     
  5. crutschow

    Expert

    Mar 14, 2008
    13,056
    3,245
    Mike beat me to the punch. My recommendation is the same as his.
     
  6. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    The Light goes out during the time the button is pushed. Read above...
     
  7. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    I beat ya, I beat ya...
     
  8. Element1

    Thread Starter New Member

    Feb 6, 2010
    8
    0
    ok so i was close, just didn't know how to do it, thanks
     
Loading...