I have already discussed about stepper motors, types of stepper motors, internal structure of a stepper motor and also how to design a stepper motor control circuit in STEPPER MOTOR CONTROL USING ARDUINO project. Stepper Motors can be categorized between Servo Motors and DC Motors as you can control the angular position of the shaft as well as rotate the shaft freely in either direction.
If you remember the previous Raspberry Pi Tutorials, we have seen HOW TO CONTROL A DC MOTOR USING RASPBERRY PI and also HOW TO CONTROL A SERVO MOTOR USING RASPBERRY PI.