For all of the many times I have done it, I have never gotten tired of typing a command, or clicking a button on a screen, and watching something happen in the real world.
An LED turning on, the click of a relay, or even a motor beginning to spin… These represent a moment when the seemingly ethereal digital realm of our computers interact with the physical domain.
I have spent my entire career dealing in the interface between the ethereal and the physical, working where the two meet. Turning sensor readings into digital, and then turning the digital into actions in the everyday world. I played with this interface as a teenager, learning the basics. My wisely chosen college degree was tailored to this task, an electrical engineering degree with a heavy dose of computer science. Professionally I have dealt with microcontrollers, high performance analog to digital systems, and programmable logic controllers, all straddling the boundary line from digital to physical.
I think back to the hundreds upon hundreds of times I have drawn something on a computer screen… A mounting bracket, a printed circuit board, a telescope. Something that existed first as a file of bits on a hard drive to be transformed into a physical reality. Machined from a block of aluminum, etched at a board shop, or squirted from the nozzle of a 3D printer. A thought transmogrified to a physical object.
Performing some routine tests on a newly installed aquaculture controller I think back to all of this… The simple click of a relay again reminds me of the magic, that little thrill I first felt pressing a key and watching an LED turn on so many decades ago as a teenager hacking an Apple IIe computer.
What was simple has grown ever more complex… I look at the workbench in front of me and click a button on the screen of my laptop computer, a Python script then turns that button press into a request, that query is sent across a WiFi network connection to an access point. The packets are transmitted to the network router on a copper cable.
From that router the request is then passed to another router via a hardwired link. This second router transmits the request to a different WiFi access point where it is transmitted via radio to a small microcontroller. The microcontroller software decodes the request, which changes the voltage on an output pin, which drives a transistor, which powers a relay, which powers a solenoid valve and salt water begins to flow.
To turn on that valve at least six separate computers have had to pass along the request, probably more. It is a staggering amount of tech that has to work to make even a simple thing happen, tech so many of us have simply forgotten about or never realized existed despite using these systems every day. And this is just from one end to another of our facility. In reading this webpage it is possible the bits have passed through dozens of compters to reach your screen.
I think about the parts of that chain I have built… I wrote the Python script, I purchased, installed, and configured much of that network equipment, I designed and built the microcontroller system at the far end, I wrote the software running on that microcontroller, and I wired the relay and plumbed the valve. It took a lot of work.
For all that I accomplished it would be worthless without the stupendous amount of creativity and labor that went into creating the various bits of software and hardware I used. The laptop, the routers, the radios, the microcontrollers and processors, all of the other components and circuitry that support it all. These building blocks represent the work of so many engineers, programmers, technicians, and assembly line workers across the globe.
For most, what is done in the digital realm stays in the digital realm. Conversations, photos, games, the records of our digital lives. But some machines use this ephemeral existance to modify the real world. This is the place I live and work in.
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