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Bench Talk for Design Engineers

Bench Talk

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Bench Talk for Design Engineers | The Official Blog of Mouser Electronics


Walking Ham: A Day in the Life of a “Walking Dead” Amateur Radio Operator Mike Parks

Ever wonder what it would really be like if you combined a zombie apocalypse with technology? Here’s a stab at it:

“CQ CQ CQ. This is November One Hotel November Papa. Anyone got their ears on?” I ask the ether. Still, nothing but static. It’s been like this for months now. My stomach is grumbling but my desire to find someone, anyone, is too strong to breakaway from my radio. Not to mention the fact that those roaming monsters scare the heck out of me. Leaving the relatively safe confines of my ham shack is decidedly unappealing except for the annoying little fact that my food supplies are running low. Very low.

Weary-eyed and hungry, I check my batteries. A week of consistent bad weather has taken its toll. There are just not enough photons hitting my photovoltaics to recharge the batteries. I enter my radios settings menu and lower the transmit power yet again. It’s not ideal, because lower power means I can’t transmit as far and I am unlikely to punch through the background noise. But I tell myself it’s better than no radio at all. At this point, even static has become as soothing a sound as the voice of a good friend.

In my previous life I was an electronics engineer and still find some value in the skills I procured before this apocalyptic nightmare began. I have been tinkering with energy harvesting technologies for a while now. Before the walkers took over our world I started out messing around with energy harvesting kits from Mouser Electronics, then I got into wind turbines and finally, thermoelectric generators (TEG). Wind however, like the sun, is unreliable but I can easily stoke a fire. The TEG is a simple yet ingenious little device that relies on applying heat to two dissimilar metals to generate an electrical current. In addition to the electricity, the soft glow of a flickering fire is a great way to calm the nerves. The flipside of course is that it means I have to maintain a supply of firewood which, like my food supply, is also running low.

Again, my stomach rumbles. I wince at the pain my hunger is inducing.

“Time to venture out,” I tell myself. As I gather my gear, I decide now is as good a time as any to try out a little project I have been working on. My constant worry is that every minute I am way from my radio, there is a chance that I will miss finding other survivors. To overcome that fear I repurposed a BeagleBone single board computer that I had once used to control watering my lawn. Beaglebone is open source hardware, which better enables me to alter it to fit my purposes and new priorities. By combining the BeagleBone with a few other components, I built a beacon that keys the radio every few minutes and transmits some information about myself and my location. At least that’s what I hope it does. Without a fellow ham to test this contraption with over the air, I am going to have to take it on blind faith that it works.

It takes only a few moments to wire up the various connections between my computer and the radio. Then I take a deep breath and flip the switch. A moment passes as the system comes to life and then, without my intervention, the BeagleBone keys the radio and begins to transmit my message. Success! It is a small yet rewarding victory. I am now a little less apprehensive about venturing out. Well, as comfortable as one can be with biters seemingly lurking behind every shadow.

It’s not even twenty minutes before I stumble upon my first group of lamebrains.

“Crap,” I sigh exasperatedly. In the small town I now call home, there are not a lot of places to collect needed supplies. This group of walkers is blocking off the entrance to one of the last well-stocked stores in easy reach of my hideout. So I wait. The problem with waiting is it means you have time to think. There was time a I would have given just about anything to be able to stop and smell the roses given the hectic lifestyle I used to live.

At first I just listen to the incomprehensible moans of the creepers and wonder if their groans have meaning amongst themselves. Then my mind drifts to all the things I will never get to accomplish, like selling my BuddyBot cat laser toy or finally learning Morse code.

Wait a second. That’s it! I carefully make it to my feet. I begin my way back to my shack as quickly and as inconspicuously as possible. This is an idea that just can’t wait.

I make it back to the shelter safe. I stowaway what supplies I did manage to gather. Then I light a fire so I can get the TEG to begin to recharge my radio batteries. While the electrons slowly flow back into my batteries I begin to draw out my idea.

Regrettably, I never learned Morse code. I just never developed an ear that could distinguish the dits and dahs. But I could build a device that could translate Morse code into written text and vice versa. If there are survivors out there than chances are they are living with same constraints that I am facing. Lack of reliable power sources means I need to be thrifty and inventive. Sending Morse code instead of voice means I can conserve power without sacrificing distance. And having the BeagleBone doing the translating means I can converse in Morse code without having to learn Morse code! After a few hours of work, I have a device ready. Once again I hold my breath as I turn the radio on.

At first there is nothing. I slowly twist the tuning dial as I search the 20-meter band.

Noise. I keep turning the dial for what seems an eternity.  Then I hear it...


--         ---           ..-        ...      .       .-.



Check out Chapter 2 here: https://www.mouser.com/blog/walking-ham-chapter-2-to-catch-a-zombie



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Michael Parks, P.E. is the owner of Green Shoe Garage, a custom electronics design studio and technology consultancy located in Southern Maryland. He produces the S.T.E.A.M. Power podcast to help raise public awareness of technical and scientific matters. Michael is also a licensed Professional Engineer in the state of Maryland and holds a Master’s degree in systems engineering from Johns Hopkins University.


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