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Technologies Review | August 19, 2017

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Why doesn’t my Garage Door Opener open my Neighbor’s Garage, Too?

Why doesn’t my Garage Door Opener open my Neighbor’s Garage, Too?
Josephbker

Most of us use a garage door opener several times a day and do not know how they work. You might be surprised as to how the modern garage door opener has changed over the last 50 years.

That being said, why does a garage door opener, which is identical to a neighbor’s, not open their garage door, too? We’ll get to that.  First, here’s a brief history of the garage door opener.

Garage door openers first became popular in the 1950s shortly after World War II. They used a small remote device that transferred a radio signal to the garage door receiver located inside the garage. When the radio signal frequencies matched, the door would open.

The remote system did not always work as intended. The garage door opener operated on a radio signal system that only had a limited number of signal frequencies to match. Why does that matter? Simply put, any garage door opener that operated on the same radio frequency could be opened! One could drive down the street, pushing the garage door opener button, and watch as their neighbor’s garage doors opened and closed!

To counter this issue, the garage door opener went through some revisions. DIP switches were added to both the remote and the receiver inside a garage. These DIP switches contained eight different tiny switches that were soldered to a circuit board.  By setting the DIP switches inside the transmitter, you controlled the code that the transmitter sent. This eliminated the shared frequencies problem. The garage door only opened if the codes matched. While this was a huge improvement, there were still a few security issues that needed to be addressed. Because the frequency never changed, a thief could identify the radio-frequency identification (RFID) tag to open the garage.

Today, garage door opener remotes and receivers both contain a computer chip with identical code generations. Each time the remote is clicked a new radio signal is transmitted, generating a new code each time it is used.  When the codes sent between the remote and receiver match, the garage door opens.

So, to answer the question posed at the beginning of this article, the computer chip prevents users from opening the neighbor’s garage door every time we press the button on the remote. Fun fact: Most garage door opener repairs have to do with the computer chip, and not the other parts.

For more information on the history and evolution of the garage door opener, check out this short video from the Modern Marvels website.