And here’s plenty of code that will read quadrature on an Arduino or other processors. We’ve seen similar hacks done with hard drive motors which are quite similar, by the way.

Rather than write a bunch of stepper motor code himself, he installed and ran a four-axis fork of grbl on the Arduino, turning it into a stepper motor controller.

I like this one - a super impressive Arduino-based barometer for measuring air pressure. There's something satisfying about the link with nature, a tangible connection with outside weather.