Where I actually started, and it isn't the thermostat
Before telling the story, I need to say who did it, or none of it will make sense.
I'm a senior software engineer. I can design systems, read a spec, debug ugly problems. About hardware I knew close to nothing. The only program I had ever written for an ESP32 was a loop that blinked some LEDs to a beat: a digitalWrite() inside a delay(), and the satisfaction of someone who has just invented fire.
I had never soldered anything that mattered, never used a multimeter with any real understanding, and the basics of electronics — logic levels, what happens if you feed a module 5V instead of 3.3V, what a differential line even is — I knew only vaguely, the way you know a subject you've never actually had to deal with.
What I do have is the DIY habit. And there is a very specific satisfaction that people who only write software never fully get to feel: the code you write every day lives inside a screen, and when it works, a green test tells you so. Nice, but abstract.
