The idea of using a spare garage door transmitter to control my two garage doors seems to be the less complicated.
Since the OSPi system drives solenoids for the sprinkler valves, and the solenoids I use are less than $10 at Home Depot, how hard do you think it would be to build a mount so that a solenoid plunger could push a transmitter button? …
I’ve seen people mod the transmitter. Generally they open the transmitter and put a relay between the button contacts. So basically it’s the same method I’m going to attempt, but they are using the transmitter button instead of the wall button.
Using a plunger would work too, but it will require some sort of anchoring/framework what would keep everything lined up correctly. It would probably be bulkier and more prone to mechanical failure. But it might be simpler to implement if you don’t want crack open a transmitter.