iPhone (or Android) garage door opener

Instead of replacing the batteries in my garage door opener, I decided to rig up a system that would allow me (and my wife) to open our garage door from our cell phones. This made sense to me instead of replacing the batteries, and my wife eventually came around to the idea as well.

This is how I did it.

First of all, I can't take credit for most of what I did here since I drew inspiration from this Instructables project: IPhone Garage Door Opener but I can at least add a bit to the body of knowledge around this idea.

The tools required:

  • A garage door opener (I have a Liftmaster professional with a Liftmaster security+ controller). Most work the same way.
  • Belkin Wemo switch
  • Relay that activates on 5V (similar to this one)
  • A simple USB cell phone charger (or 5V DC wall wart), similar to this one
  • Some wire cutters

Most garage door openers use a simple method to either open or close the door: there's usually two wires connected to the garage door opener. If you want to open the garage door, simply short these two wires. If you want to close the garage door, you just short the wires again. This is all the garage door remote control does.

So, with this knowledge, all you have to do is identify which wires are being shorted, and then install your own internet connected relay that does the shorting work for you. You can hook this up along side your existing garage door opener so that both methods (your normal method of opening/closing your garage door and the new iPhone method) work harmoniously together.

This is what my garage door opener looks like:

Attached to the wall of my garage, I have this controller:

So, now for the real work (which is actually quite simple). First, here's an overview of what I did:

The guts of this project is really just the small relay that runs off of the +5V signal from the USB cell phone charger:

The relay is activated by a +5V signal connected to a simple cell phone charger plugged into a Belkin Wemo switch. I've configured the relay to be normally open, so that when a +5V signal is applied, the relay closes and shorts the two wires connected to the garage door, otherwise the relay is open and the two wires are not shorted.

I would suggest testing this relay and setup with a simple multimeter before hooking up to the garage door opener. Set the multimeter to detect continuity between the two wires meant to connect to the garage door opener. When the Wemo switch is turned on, the multimeter should detect that those two wires are connected to each other, when the multimeter is turned off, the multimeter should indicate that there isn't a connection between these wires.

And that's it! I've assumed that the Wemo switch is already configured, something fairly easy to do. Now, all you have to do to open and close your garage door is to open up the Wemo app on your phone and turn on the Wemo switch:

A few caveats, warnings and tips

  1. When using the wemo app to open and close the garage door, you'll actually have to turn on the wemo switch (via the app), then turn it off again each time you want to open or close the door (this is two taps each time). The reason for this is that the garage door opener opens or closes when contact is made. So you need to make contact by activating the relay, then you need to release the contact by deactivating the relay so that the door is ready for the next round of opening/closing.
  2. Using this simple setup, you'll have to be careful not to accidentally open the garage door while you're away from the house because there is no way of telling if the door is open or closed. This means that you could activate the wemo switch by accident while you're away from your house and the door could be open without you knowing. I've been thinking about how to solve this issue, but it would require the use of something like an arduino to detect if the door is open or closed or perhaps with some fancy IFTTT.com script.
  3. As indicated in the Instructables tutorial, it is also possible to set up Siri on your iPhone to open the garage door. This relies on sending IFTTT a text message, the problem is that I live in Canada and IFTTT lives in the US and so each text message would cost roughly $1.