Inspired with the solution here, I roll up my own garage door switch without any relay. I have been developing this for a couple weeks and document them in the Environment sensor thread. I am really close to install it on my garage. I need to buy one more reed switch. I think it is time for me to share my solution here. Perhaps, it could help someone here.
I notice the remote (at least chamberlain, liftmaster and craftman) is a 3V device. I think it should be safe to connect the buttons to a 3.3V MCU and toggle GPIO to simulate a button press. I have a drawing on what I think about how the button works.
I used a clone arduino UNO which operate on 3.3V. I hook it up to Zigbee Environment Sensor which also act like a Thingshield. Here is how it look like. I transplant the GD remote on the second mezzanine.
Here is 37 seconds demo video.
Since, it is over kill to use arduino to just push a button, I added a few sensors on the board. I have a couple contact sensors. I have motion sensor and vibration sensor hook up as well. Here is how they look in hubitat.
As pictured, I am able to click buttons on my remote. I can monitor temperature, humidity, pressure, light of the garage and detect power outage in the garage. I am hoping that I can use the vibration to tell me the door is moving. I am able to detect motion inside the garage. At this point, I am able to detect whether the door is fully open or closed with 2 contact sensor.
I am sorry if this is too long. I primarily just want to share that the garage door remote may work without relay. You can simulate the button click with simple GPIO toggle with an 3.3V MCU. Toggling this way is very fast. I set mine to toggle in the order of 10 milliseconds which is probably unwise to do with a relay.
