Defeated By A Garage Door Opener

Murphy rules.

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I’m a big fan of Mentour Pilot.

In his analysis of aircraft disasters and near-disasters, a point Petter Hörnfeldt often makes is that the big problem is almost always the consequence of the convergence of multiple smaller problems: a defective instrument plus an inattentive pilot plus lack of good cockpit communications, etc.

My story is about a hugely less consequential problem: my wife and I were deprived of the benefit of what the late Andy Rooney called the greatest invention of the twentieth century: the remote garage door opener.

Our garage door opener was intermittently not working, with the problem occurring more frequently as the months went by.

Murphy begins the attack

So I cleaned the battery contacts in the remote. Didn’t help.

Like most people we have two remotes, so of course had I tried the spare. For a short while it worked a little better so it became the main one but then the deterioration continued.

Cleaned that one’s contacts, didn’t help.

As Murphyⁱ would of course have it, the problem would show up during bad weather, compelling me to walk through the rain to unlock and enter the front door, then go through the house to push the wall button to open the garage (which worked fine, so the problem isn’t in the door opener motor and drive) then back through the rain or sleet to the car and drive it into the garage.

Fighting back

Obvious first remedy: go out and buy a new battery. Conveniently they come in pairs, as most people, like us, have more than one remote.

Replaced the batteries in both remotes and went back to using the original main one for reasons I don’t recall.

The problem continued. Conclusion: the problem is in the radio receiver.

Much time spent fiddling, testing, reprogramming, etc.

No dice. Still intermittently, and more frequently, not working.

Assumed that the refrigerator or other motor-driven appliance in the house was generating interference with the radio signal from the remotes. Conclusion: live with it.

First clue uncovered

Then one day I happened to look closely at the “new” batteries I had put in the remotes. They had apparently been hanging undisturbed for years at the small convenience store where I bought them, as their expiration date was a couple years past. The makers of these devices clearly chose to create their own battery spec instead of using plain old AA or AAA batteries that turn over rapidly on store shelves, as some kind of devious attempt at market control. Fie on them!

But finally, I thought, I had found the problem.

I go out and get new, fresh batteries with expiration dates long after The Singularity or The Apocalypse (depending on whom you follow) from a high-volume retailer.

Victory? Not so fast…

Replaced batteries in both remotes, take one and test it.

Damn! Problem persists.

Cleaned the contacts, didn’t help.

Called the garage door opener’s local vendor, who of course patronizingly insists that it’s probably a battery problem even after I recite every step in my ordeal. No, they won’t schedule a service call until after I bring in the remote for testing because of course they “know” it’s the battery.

My wife and I live with the problem for a while because of course I’m not going to take my time to go there just to prove that the problem is not what they’re so sure it is.

Then one fine day the main remote found its way somewhere under the car seat. Couldn’t find it right away, so grabbed the spare remote from the house.

Pull out of the garage, get ready to do the go-into-garage-push-the-button-run-jump-over-the-light-beam dance to close the garage door, but first gave the spare remote one hopeful but probably futile button push.

It worked.

OK, with both the remotes you still get lucky once in a while, so I try again, this time with the door closed.

Door opened!

Wait, what’s this? The spare remote has been functioning all this time?

Penetrating Murphy’s defenses

Yup!

Turns out the main remote was indeed defective, while the spare remote was fine all along, as long as it had good batteries.

The sequence of multiple problems conspired against our peace of mind over two years, but since the day of that discovery my wife and I have joined contemporary society in enjoying the ability to enter and exit the garage without getting out of the car – all at the push of a button.

Somewhere, Andy Rooney is smiling. (Which would be a first.)

The Lesson

Problems are not entropic. As Mentour Pilot reminds us, problems gang up on you.

There’s no getting around it: Murphy rules.

But Wait, There’s More!

While we’re on the subject of garage door openers, older ones pose a risk due to the fact that the “secret” code to open the door is sent in the clear. Actually the newer ones are also sent in the clear but they use “rolling codes,” where both the remote and the receiver are synchronized to generate a new, unique code each time the remote is used.

That is not encryption. It’s the old OTP or “one time password” system based on the “one time pad” idea that’s been used in semi-secure military communication for centuries. OTP is supposed to prevent replay attacks, since an intercepted code won’t work again.

If you have the older type, anyone can set up a radio receiver near your garage, capture the code, wait until you’re away, replay the code and, if your garage is attached, enter your home.

One of these days someone (perhaps you!) will come out with a garage door opener that uses asymmetric cryptography for true security. This video explains how it works in the general case, but it’s exactly the same process for a wireless remote – just keep in mind that “your device” means the remote and “the server” means the door opener.

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About the Author

In 1981 Wes Kussmaul, working with friends at the MIT Joint Computer Facility, created the world’s first online encyclopedia, implemented using what he calls “the world’s worst business model.” Over the the next year the addition of social features transformed the encyclopedia into the more sustainable Delphi social network, which in 1993 was sold to Rupert Murdoch’s News America Corp.

Wes is the author of four books about bringing accountability with privacy back to social networks. One of those books caught the attention of a group at the ITU, a United Nations agency, while it was building a global PKI-based source of trust that resembled what the book advocated. Wes announced its re-launch as The City of Osmio in a 2008 presentation to the United Nations World Summit on Information Society. Wes is also the creator of Stoanova, an approach to Stoicism as it applies to problem solving.

Wes is the founder of The Authenticity Institute, a provider of a PKI platform to licensed Authenticity Enterprises, which may be seen here. The outcome of the work of those Authenticity Enterprises may be seen at Authentiverse.

i For Millennials: “Murphy’s Law” says that “anything that can go wrong will go wrong.”