With this circuit you can make a stepper motor do just about anything it will need to do in robotics application: rotation to the left or right, in full-step or half-step mode.

Stepper motors convert electrical pulses into mechanical movement. In applications like hard disks, printers and photocopiers (to mention but a few), stepper motors are used for rotation and/or accurate position control of mechanical assemblies. Every stepper motor has one permanently magnetic axle called the rotor. This is surrounded by a fixed part called the stator. Usually, stepper motors have four stator wires with two or one common wire, which is normally connected to the positive supply voltage.