My kids are notorious for opening the garage door and leaving it open. When a neighbor called me at 2 in the morning to let me know the garage was open, I decided that I was going to figure out a way to monitor the garage door from my computer.
This job took me about 4 hours. My friends and neighbors will be shocked to find out I did it, because my wife is the handy-man around the house. She asks for the power tools for Christmas while I ask for the NewEgg & Best Buy gift cards. If you are truly handy, this should be a quick and simple project.
The first step was to get me some z-wave hardware. I ordered an Evolve LFM-20 relay and an Aeon Labs Door / Window Sensor. The LFM-20 would be used to actually open and close the door, while the sensor is used to tell me if the door is currently opened or closed.
Door sensors are sensitive to metal, otherwise I could have mounted them directly to my garage door railing. Instead, I needed to figure out how to raise them "above" the rails and still have the paired sensor halves match up.
I went to my local hardware store and purchased a "Garage Door Top Bracket." After removing part of it and forcefully bending it into a desired shape, I was able to mount it to my garage door along with a sturdy piece of 2x4. This piece would go up and down with the garage door.
On the other side I mounted a 2x4 to the fixed side of the door. This part wouldn't be moving anywhere. Here is the finished sensor mount:
I purchased a $5 plug kit and wired it onto the black/white/green wires of my LFM-20 relay. My garage door opener is conveniently located right next to an outlet, so this worked out great.
The next step was to wire the Evolve switch into a parallel circuit with my existing garage door opener button. The "diagram" of how I did it looks like this (please don't mock my artistic ability!)
One problem I ran into with this setup is that while the Evolve LFM-20 is active, the normal button used to open the garage door won't work. The fix is to find a way to shut the relay off just after it activates. For this, I used InControl's "auto-toggle off" feature to turn the relay off after a few seconds.
Using InControl, I'm able to monitor my garage door. When it's open past 9 PM, I get a text message at which point I can use my Android phone to close the door.
Here's a complete shopping list of z-wave items to make this work:
Most of these items can be purchased in a package
to save you some money.