We Don't Need a Microcontroller in Every Single Design
July 15, 2026 · Jeffrey C. Dunnihoo
I watched a kid’s eyes light up at our book fair when a simple J-FET transistor switched an LED with nothing but static electricity from a rubbed plastic cup. No code, no battery switch, no microcontroller. That moment is scarce. We’ve convinced a generation or more that every blinking light needs software and a 32-bit brain. My day job fighting reliability battles in real silicon has taught me otherwise.
At a recent book fair, Pragma Media rolled out a simple demo board alongside the launch of The Wonderful Wizard of Electricity. Just a J-FET transistor in an ultra-basic open-drain setup, an LED, and a current-limiting resistor. No battery switch even, really. Kids rubbed wool on a plastic cup, held the charged plastic near the unconnected gate, and watched the LED fade on and off as they drew the cup near and away. Not touching anything. No switch. Just Asimov’s “sufficiently advanced technology, indistinguishable from magic.”
The little faces peering over the table... that spark in their eyes when they realized something invisible was controlling the light. Priceless. We weren't doing the tired old battery-switch-bulb routine. This was "hey, wait, how does it know?"
In the educational appendix of the book, we tell the story of Thales of Miletus, who noticed that amber rubbed with wool would attract bits of papyrus. He figured the amber must have some kind of soul, (ψυχῆς - “psyche”), as Aristotle claimed he called it. If not a soul, how else could it remember to pull on stuff? Today we call it electrostatics, and it's the same invisible force that still zaps our semiconductors and makes sweaters and socks hug each other.
My day job involves electrostatic analysis and keeping ESD threats from destroying microchips. Most folks get magnets and static cling. But relating a charged plastic cup to a transistor switching a light is fresh territory for most kids and their teachers.
When we asked the kids what they thought made it work, they said: "Magic?" "A trick?" One super-confident boy, with the satisfaction of remembering something he had learned yelled "It has code in it!"
My 11-year-old girl running the demo at the time didn't miss a beat: "It doesn't need code. It's a transistor!"
To be fair to the code kid, the modern "Hello World" for embedded stuff is usually a GPIO blinking an LED with some microcontroller. That's probably the only way he's ever seen a light turn on and off.
ARM, for example, has educational projects on their website like the Smart Home Controller on a Raspberry Pi 5, complete with quad-core 2.4GHz CPU, and 16GBytes of DRAM to run small language models locally. All so you can toggle some LEDs and imagine your house is thinking.
We're talking about a $299 single-board computer (thanks mostly to that 16GB of RAM for the LLM) to blink an LED. No. Do not want.
And I'm not sure I want a non-deterministic language model deciding what "secure the house" means when it gets late at night.
"Turn on living room light."
"I want to watch my favorite show."
"It's getting late, secure the house."
Lay down for bedtime confident that the LLM didn’t hallucinate about locking the doors?
This is exactly how we end up with microcontrollers in our toasters and out-of-stock controller boards in washer/dryers that cost more than a new appliance. I'm not claiming you won’t get extra magical gradations of toastiness on your pop-tart from a 2GHz 32-bit CPU. And I'm not saying every washing machine should go back to pure mechanical timers (though ours do just fine, thank you). But right-to-repair rabbit holes aside, we're not teaching kids to build generic, cost-optimized controllers that last as long as the appliance and can actually be replaced when needed.
Dishwasher functions haven't really changed in fifty years. Cycle times, sprayers, racks... a universal (per brand, at least) controller with standard connectors could handle it. Manufacturers could still churn out new models every season for the showroom floor, but they'd slash aftermarket parts headaches and maybe even build some Speed Queen-style loyalty instead of the usual landfill churn.
Jimmy Buffett probably ran his Margaritaville blender with a toggle switch, and he did all right.
Between tech companies eager to hook the next generation on their proprietary ecosystems and appliance makers leaning hard into designed obsolescence (if not outright embracing the Landfill Economy), we've got to keep an eye on what our kids are building. LEGO robot garage... or a 64-bit Tower of Babel?
Really, though. Do we have a shortage of memory spiking prices, or are we allocating too much memory to blinky light controllers?
We don't need code in everything. Sometimes a transistor, a switch, and a little electrostatic soul are more than enough.
Let's show the kids that version first. The rest can add if they actually need it.