I already have the gates up and running and they have remotes. Each (one is a Gemini, one is a Centurion) have a TRGGER pin that I believe you can hook up to a switch to let the gate open or close.
The problem with the Sonoff switches mentioned in this thread is that they don't just give you a relay with "free" connections -- it is wired up to the mains too, so the idea is you can use the switch to turn on/off mains powered devices directly. In my instance I just want to trigger the TRIGGER pin, so a relay separate from the mains should be better.
That being said, I noticed now that Sonoff also has a couple of additional offerings, including a Sonoff SV (Safe Voltage) switch (
https://www.netram.co.za/3600-sonof...velopment.html?search_query=sonoff&results=11) designed to run from 12 - 24V and switch small voltages, and from what I could gather you can also disconnect the relay from the source, so this is likely what I want.
My next challenge is
a) is my wifi strong enough to get out to my gates (likely not)
b) how can I pick up if the gate is open or closed?
For a) I'm thinking of just opening one of the Centurion remote controls and connecting the relas to the buttons directly. I have 2 extra remotes and that way I don't have to install anything additional into the gate boxes. And it keeps the secure connection bteween the two and I know it covers the distance.
For b) I'm looking at the Sonoff RF bridge (
https://www.itead.cc/sonoff-rf-bridge-433.html) -- which basically offers you Wifi control over RF devices, including detection of RF-based door sensors and PIR sensors (they sell their own for cheap). So I could use that to detect if the gate opens or closed. The main purpose here is to have an alarm inside the house if the gate is left open, or my mother-in-law arrives without notice (she has a remote).