How it all started
About three years ago my wife asked me: "Honey, what do you think the temperature is today?"
I told her to check her phone. She gave me a look and said, "No — in here. In the apartment."
The next day I remembered we had a clock with a built-in thermometer somewhere. Found it, put batteries in it, problem solved. But I couldn't stop thinking: how do digital thermometers actually work? Temperature is continuous — how does a microcontroller read it?
That question sent me down a rabbit hole. I learned about thermistors. Then about Wheatstone bridges. Then about instrumentation amplifiers. A few weeks later I had a thermometer built around a thermistor, an AD620, and an ATtiny85 — a chip with 8KB of flash and no business running anything sophisticated.
