I've recently gotten into stepper motors, and I'm wondering if a stepper motor can be controlled via a keyboard. (For example, pressing the space bar would make the stepper rotate right, etc.) By the way, I'm not asking about any stepper motor in particular, whatever works best.
Sure... just read the keyboard and move the stepper.
That's a pretty general question, so you got a pretty general answer.
If you have a PS2 keyboard, you can read from it using this library:
Here's an example of a person reading from a USB keyboard with Arduino. Much more complicated: http://www.circuitsathome.com/mcu/how-to-drive-usb-keyboard-from-arduino