I was wondering if I buy a second wall mount door control, identical to the one supplied, can it be wired in in parallel from a second location with a two wire circuit paralleled to the existing at the door opener from the first control?
I think diy.stackexchange.com/q/81117/1300 is relevant– Rory AlsopApr 13, 2019 at 16:35
Yes you can wire up to 4 opener buttons in parallel to the same opener. I know this because I figured it out while developing ratgdo.
The 882lmw wall mounted button requires 8.5mA of power. Other models will draw slightly more or less power.
It takes 50mA to pull the 12v line to ground (the buttons pull the line to ground to send the encrypted serial commands to the door opener).
50mA is the absolute maximum amount of power the 12v line can provide - however you need to leave some headroom.
50mA - (4 * 8.5mA) = 16mA of headroom.
1This could do with a citation from relevant manuals or other sources. Jul 12, 2022 at 13:45
Where does the limit of 4 come from? Is this specific to a certain brand? Do you have personal experience doing so? Give us a little meat on this bone...– FreeManJul 12, 2022 at 13:54
please see my edit Jul 12, 2022 at 14:57
1OK, now you get my up vote and a great deal of my interest! I ended up using an ESP2866 with a relay to talk to HA, then soldered the wires across the contacts of the activation button on my wall mounted button. This looks a lot cleaner. Nicely done! And a star on GH. Unfortunately, I don't think my opener falls into the category you support, but I'm interested in progress in the future.– FreeManJul 12, 2022 at 16:46