Turns out that my garage door opener (a Chamberlain HD220) is too new and fancy to work with a general door opener like this one. This Z-Wave opener has a relay that goes in parallel with the wall button and pulses it to simulate a button press. The button on the wall that came with the Chamberlain unit is actually more than just a contact -- there's a whole printed circuit board behind it and presumably it sends some sort of serial command when you press it.
|A poor quality picture of the board behind my wall button. Note the clicky switch SW2 on the left.|
Even though the wall button isn't just a button, there is a button on it (SW2 above). The relay in the Z-Wave unit just has to go in parallel with that button. It wasn't too pretty, but I soldered on a hobby JST connector (not the ideal wire because of its size and many strands, but it works) so that I could do a longer wire run to the Z-Wave unit which is next to the physical garage door opener.
|The button board with JST pigtail connector.|
|Close-up of the switch and solder-job. I'm not proud.|
The bell wire that pigtails out of the Z-Wave unit wasn't long enough, so I extended it with some old telephone wire that I knew I'd been saving for something, but any wire with 2 conductors in it would work.
|The button back together and on the wall.|
I got the idea from this forum post. Note that this should work on Liftmaster, Chamberlain, and Craftsman garage door openers that have smart buttons.