Hi, Ive been away from the forum for a little while, but yes this is something you can setup fairly easily.
However, what you wont have without doing some extra work and installing extra devices is the ability to know the status of your garage door - is it open or is it closed.
To make it all a little neater, you need the following:
Zwave relaywith dry contacts for switching alternative voltages. I used fibaro FGS212 (do not get the 213 as this cannot switch a different voltage to the one powering the device)
Zwave door open/contact sensor
Smart App - Ask Alexa - see here: [RELEASE] Ask Alexa
LGK smart app to link virtual and real garage door - see here: New smart app to link the virtual/simulated garage door device with two actual devices
The instructions are self explanatory in the threads for the two smart apps linked above, however I’ll describe the resultant functionality:
The sensor is used to determine if the door is open or closed. The relay is wired such that it activates only for a moment and simply mimicks the button press on the unit inside the garage (you may need to find the wiring diagram for your particular garage door opener to discover which contacts are used to mimmick a button press)
The smart app linking a virtual garage door to a real one allows it to double check the status of the door after a command is given and set the virtual garage door indicator appropriately. i.e. You ask alexa to close the door, but it doesnt happen (door blocked or for some reason zwave is down etc). If the door sensor doesnt show the door as closed within around 15 seconds or so, then the virtual garage door is set to show open - so you can see the real status of your door, not just what you last asked smartthings to do.
The integration with AskAlexa allows you to use more natural commands, such as “open garage door”. It also gets you round the issue of Alexa by default not allowing you to open a gagare door directly with that sort of command. BTW, this is done for obvious reasons, as an intruder could easily shout “alexa open the garage door” through an open window.
Ask Alexa will also allow you to create a “report” so when you go to bed at night you can ask for this and it will tell you the status of any doors and windows (including the garage door/s if you wish). So you know if the door is open or not if it is not within sight of a window.
Hope this helps 