Scott B. Weingart goes into great detail as he takes us along on the journey of a text message. How detailed? Here’s a bit from the part about typing the message on a phone’s screen:
With each tap, a small electrical current passes from the screen to her hand. Because electricity flows easily through human bodies, sensors on the phone register a change in voltage wherever her thumb presses against the screen. But the world is messy, and the phone senses random fluctuations in voltage across the rest of the screen, too, so an algorithm determines the biggest, thumbiest-looking voltage fluctuations and assumes that’s where she intended to press.
So she starts tap-tap-tapping on the keyboard, one letter at a time.
A surprisingly enjoyable read considering how deep into technical details it goes.