The goal of this project is to be able to open a garage door from a phone. I had a Shelly 1 PM on hand, so figured on using that. However, I soon learned that the relay in this device is hard-wired to the line voltage – probably something to do with the current measurement circuitry in it. However, it was a fairly simple matter to add a RIB relay to provide the isolated relay. I built the entire setup into a cheap plastic electrical box, and then installed near the garage door opener:
The output of the relay is wired in parallel with the wall switch for the opener.
A timer was enabled in the device settings that turned off the relay 1s after it is engaged – this allows the device to send a pulse to the opener each time the relay is engaged.
Now, using the Shelly cloud app, the door can be opened – even remotely.
Using a Shelly Plus 1, this would be a very simple project, as the RIB relay would not be required.