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How to integrate your car's HomeLink buttons into your HA system

Garage Car HomeLink Remote

It seems nowadays, most modern vehicles have HomeLink or Car2U - those three little buttons designed to integrate with your garage door openers and gates. Also, the majority of houses in america have only one, maybe 2 garage doors - so there's almost always a spare button or two.
Have you ever wondered how you could very easily integrate those extra buttons into your Home Automation or Security system?
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About a year ago I came across an amazing little device that could really come in handy in the Home Automation world. It's available at Fry's and other retail establishments and ranges from $28-$38 from what I'm seeing. It's the Wayne Dalton Garage Door Conversion Module.
The idea behind it is that it's for converting antiquated or incompatible garage doors to work with most HomeLink and Car2U systems as well as the WD keychain remotes. What gets missed is that it's really a simple relay closure device that's compact and is compatible with most of these in-vehicle transmitters! Here's a link to it on amazon.

As you can see from the pictures here, it's very simple and compact... most garages have the dedicated outlets for the garage door openers with a free outlet - it's designed to go there, and has a spot for a screw to hold it in... In my case, it's plugged in there, but I'm not wiring it into the opener - instead it's connected to a wire that goes to an M1XIN that's in the garage (I put the original 14" Elk can in the garage with an M1XIN, M1XOVR and M1RB for sprinklers, inputs, etc).
The range is decent - but anyone with HomeLink should know that it's much lower range and less responsive than the opener's own control... that's life. So what can I do with it?

Well, that depends on what you have to work with. You could hook it into your security system (Elk, HAI) as a zone input - I'll get to that later. You can even hook it to one of the many input modules (Global Cache, Simply Automated, etc) - Anything that can serve as an input when 2 wires are touched together. In my case, I'm working with an Elk, and as mentioned above, I already have an input expander in the garage and an extension of the databus. That made life really simple!
Even if you don't have a full Home Automation system, just pairing one of these with an input adapter for whatever lighting system you use can give you basic control of lights or other things around the house.  Also, if you don't have an input expander handy, you can always pair it with something like the UPB input module above and program your HA system to watch for those links - saving some wiring hassles but still getting the same effect.

Once connected to the panel, I have a few options. I could set it to a normal non-alarm zone and run it entirely through rules... that would work fine and I could do whatever I want. However in my case, this "third button" is set to serve a single purpose - which is to close all garage doors and arm the alarm away. Because of that, I went even easier - and set the zone definition to Keyswitch Momentary Arm Away. That means any time the button is pressed, it does the Arm Away and runs the associated rules, which include turning off the garage lights and closing any open garage doors. This is my visual indicator that all went well. If the garage door doesn't close, there was a problem Arming Away.

Also, if you really do have incompatible doors, it's a good retrofit option for old openers.

One tip - for HomeLink you sometimes have to program it to a remote, then teach the newly programmed button to the opener. You can purchase one of these remotes to train it, or do like me and use one of the spare buttons on your garage door opener remote (they usually have 3 buttons) or pick up a generic remote from Home Depot or Lowes.
Some options:
  • Integrate with existing gate or garage doors that aren't compatible
  • Build a "smart" garage door opener remote - that only operates within certain conditions (using rules that decide when it works when it doesn't, then having the security panel actually open/close the door).  If you have a car you leave outside you can use rules to disable its button while armed vacation/away or something like that; or disable the buttons when the alarm is armed night.
  • Make a smart button that, if the door is open when pressed arms the system and turns off all the lights; if pressed when closed, it turns on the lights around the house and in the garage. Or something that gives you a 10-minute bypass on the garage door before unbypassing and starting entry timer (for better control of the entry timers).
  • Have dedicated open/close buttons for running rules and actions if you want.
  • Turn on/off porch lights
  • Turn on/off christmas lights
  • Arm the alarm
  • Check the status of the alarm (have it flash lights or chirp the alarm to verify status).
  • Set back the temperature in the house; or restore it.
  • Trigger any rule on the automation panel you can think of!
I'm still working on the rules, but if there's an interest I can post them up when finished; also if people have any cool ideas or uses for this, please do share! A word of caution
I am not a fan of keeping garage door openers in the cars or having homelink setup where someone can activate it to gain access to your home.
This is the first home I've used it in - previously we had security systems in our cars and I bought the expansion modules for the car alarms that had relay outputs that could be programmed for the garage - that way the remote was on our keychain  not the car.
Here we park in the garage 99% of the time - and if we don't, I just disable the GDO at night. I don't recommend programming any buttons for any sort of "disarm" functions - I firmly believe that any disarm function should require a user to enter info known only to them (no keyfobs, keyless entry, etc).
Different cars act differently; If I recall, the BMW and the Mercedes didn't let the buttons function without the key; GMC, Ford, Nissan do...Don't use this to do something like a "Disarm Security System Silently" if your cars are always parked outside - that'd just be bad. In my case if someone broke in, the worst they'd do is arm the alarm... not the end of the world.
Disclaimer: As always, neither the author or Cocoontech take any responsibility for how you implement this; use good sense and avoid letting this built-in button become a method of breaching your home security.


Any other developments?