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.

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.