Potentiometers, or variable resistors, are a standard component that we take for granted. If it says “10k log” on a volume pot, than we fit and forget. But if like [Ben Holmes] you are … ...

Then he found the very affordable 28BYJ-48 stepper motor. After some experimenting, he came up with a smooth moving robot arm with four steppers controlled from an Arduino Mega and A4988 stepper ...

grbl is stepper motor controller firmware for three-axis cnc machines, intended to run on Arduinos with a motor driver add-on board. Engineer in Wonderland cnc-related blogs are indexed here It is the ...