The code here works with an NodeMCU and a garage opener that has connectors for an external push button and a light that should be turned on while the door motor is running.
To connect with Google Home, I'm using iotmaster.dev
To connect the NodeMCU with the door opener, given it works with 24V DC, I decided to optoisolate the connections using a couple of 4N35s mounted on a small piece of perfboard.
For power I could have used the +24V out of the opener, but that would have required to use a very inefficient linear regulator to drop down to 3.3v; or well a DC-DC converter, but that would be expensive and hard to get here.
Given I was interfacing with optocuplers, I chose to use an old cheap USB phone charger and power it thru the USB connector.
Here is the schematic:
