You only need two output pins to control a stepping motor, step and direction. So with 20 outputs you can in theory have 10 motors.
Check out the RepRap project, they have some schematics and software you can look at.
You only need two output pins to control a stepping motor, step and direction. So with 20 outputs you can in theory have 10 motors.
Check out the RepRap project, they have some schematics and software you can look at.