POST // 008 - Hidden Frequencies

A brand new school year, a completely different school, and the year that I started to hang out with Steve instead of my previous middle school friends - which was probably for the best, if we're honest.

Ninth grade gave me much more flexibility to choose electives that I was interested in. There was so much to choose from, but I had already spotted a few classes that I wanted to do. One of those was Electronics and a "programming" class.

I didn't know much about electronics, other than what I learned on my own... which was mostly how to disassemble something and cut the wires like MacGuyver with one second remaining on the clock, but I was eager to learn more about it.

I remember the first day making my way into the electronics class room. It looked more like a shop with tall work benches, tall stools, and equipment at each station. There were pull out bins of components and everything you could want. Steve and I both had that class together and we often spent class time talking about electronics, computers, and random stuff.

We started simple by making a power outlet tester and this would be something we'd use the rest of class to determine if the outlet was hot or not at our station. We gradually started learning about breadboards, what the different components did and how they worked. We were about half way through the class when we found out that we were going to have to build our own circuit for the final project. Design it ourselves, make our own printed circuit board, and build our own project box. I started thinking about what I'd do for my final project. Thankfully, I had a little bit of time to ponder it since Thanksgiving was coming up.

That year for the holiday we headed to my grandparents house near Grand Forks. We'd spend that time sitting around talking, eating, and playing with cousins. We packed our bags for the few days we'd be staying in my grandparents house and loaded up into my dads truck and started making our way there.

It was the same drive we had made a hundred times before, the exact same roads, the exact same turns. Without fail my dad always took the same short cut to reduce the travel time. That shortcut was a back country road that connected two highways and cut down about 20 minutes of drive time. And without skipping a beat, we had the same fun we had every time.

On this backroad, there's a turn, and right near that turn was a house, and for some reason a few years prior my dad thought to push his garage door opener button - and their garage door opened. I still remember the moment years prior, it was just a moment of disbelief that washed across everyone. The very first time that it happened my dad had to open and close the door multiple times just for it to register what was actually happening.

This Thanksgiving drive we did what we always do. We stopped at the stop sign and took a moment to push the garage door button and watch it open and we all giggled. For years I'm sure this family has been totally confused about what is going on with their garage door. They go a few months without any issues and then, suddenly, the garage opens or closes by its self multiple times within a weekend or the span of a few days, on those quick trips, the span of only hours. Each time we pass this house, that's the ritual, and we laugh and continue our drive discussing how they must be so angry at that garage door. We speculate about the conversations they have, the stories they tell, and the service people who come to look at it.

On the remainder of that drive, after the giggling had settled down and things were quiet again, I started to think about it a little more. All the other times I had just moved on, but this time I started asking myself some questions.

Why does the garage door opener work on our door at home and this one?

Why doesn't it work on other doors that we've tried it on?

Does it work on other garage doors?

How does the door know that this opener is for this door?

The door is sending out a signal... but what prevents it from opening all garage doors?

I would spend the entire rest of the ride thinking about this. Thinking about what I've learned in electronics class. I wanted to dismantle the opener right there, but I couldn't. So, I spent the entire Thanksgiving weekend thinking about it.

My first thought was that it must be the frequency that was transmitted. Maybe both garage doors were listening for just a transmission on one frequency and another garage door was listening for a transmission on a slightly different frequency. At first this made sense to me and I thought, maybe I could connect a garage door opener to a radio and just turn the tuner through the channels and blast out all frequencies.

After we got back home I hijacked my mom's garage door opener the following weekend when my dad was at work and took it apart. I inspected it for quite awhile, but one of the things that I had noticed immediately was a baby blue block component on it with the numbers 0-9 and tiny little white switches that moved up or down. I didn't really know what this was, but it seemed to make the most sense that it would be some kind of unique identifier. I soon realized that I was probably way off from my initial hypothesis. They can only be in an up or down state so that means that there's a combination of 2 to the power of 10 - or 1024 different codes.

I took the garage door opener outside and pressed the button. The door went down. I pressed it again, the door went up. I used my fingernail to flip the Zero switch up from the down position. I pressed the button - nothing happened. I pressed it again - still nothing. I flipped the Zero switch back down to the original position. I pressed the button - the door went down.

Clearly, the switches were the answer, but with 1024 combinations, it would take forever to try and find a garage door's code. If only there was a way to push the button and have the opener cycle through all the combinations and then display the code on a screen.

Let's be honest with ourselves here, there's no way that I was going to be able to continue researching this issue with one of my parents openers - we'd been down similar roads before and they don't end well. So, with that being the case, I used that job of mine and reached into the war chest and used some of that funding to purchase a compatible opener from my local Ace hardware. This way, I could disassemble it, modify it, or even break it, and I wouldn't have to hear about it.

I got it home, disassembled it, and there it was in all of it's little printed circuit board glory. I had written down the dip switch code and used a little electronics screw driver to flip the switches into place and tested it. And just as you'd expect... the door went up and down. Now, I just needed to make sure that I tested things when there wasn't something under the door or I closed it on my dad's head. Future Matt problems.

I started taking some time going to the local library with my mom and using the computers and Microfische to look up information and magazine articles about garage door circuitry. I printed out the things that I found interesting or things that I think could be useful in the future. Sometimes I wandered into other electronics topics and printed out those documents as well.

When I got home I would read through the information again and store it in the 3 ring binder that I "Borrowed" from our home office. I would often go back to those documents as references to clarify my understanding. Steve and I discussed the problem and concepts at great length, debated about how we thought it worked and at one point I tried to talk to my electronics teacher about how this would work, because I thought this could be a great final project... but he didn't seem to understand what I was asking, or he just didn't understand how the technology worked either.

I chose a different project and worked my way through fully designing the circuit and breadboarding it to make sure it worked. Part of the project was to go to the computer lab and use drawing software to design the traces for the circuit board and I happened to be a pro at Mac Draw II.

We printed our circuit board designs and they were sent off to a company to make silk screens for the projects. When they came back a few weeks later we used them to smear the "tar" across the board, dry for a day, then drop them into the etching solution. We'd then scrub the remaining tar off the board leaving beautiful copper traces behind. We used the drill press to drill the holes, drop in the components, and solder them. I had completed my project!

But the garage door opener had still been lingering in the back of my mind. As I continued my research I started finding new information about newer garage door technology being implemented that used a microchip and rolling codes. The dip switch days were disappearing and gone were the days of manually changing the code. I came to the conclusion that I'm now facing a transition - I don't see how I solve the problem when I'm just barely understanding this problem and this is going to be obsolete soon. My heart sunk when I realized that I was late to the game and I probably wasn't going to be able to make this work.

Little did I know, there were still a few hurdles I would have run into trying to make that project work. But I don't think those would have stopped me. What stopped me was realizing that even if I figured it out, I was figuring out yesterday's technology.

What I also didn't understand was just how many things had to line up perfectly for that moment years earlier when my dad looked at some random house along a back-country road, pressed his garage door opener, and the door actually opened.

The odds were ridiculous.

I thought about garage door technology far more than any fifteen-year-old probably should have, but I never completely stopped wondering about it. Every once in a while, the question would wander back into my head.

Could I actually have built it?

It would take another thirty-four years before I finally answered that question.

But electronics class was over.

The next semester, Steve and I had computer programming together.