With this circuit you can drive a unipolar stepper motor. It operates in full step mode. The AVR attiny2313 micro controller controls the pulses for the stepper motor. The pulses are amplified by the ULN2003 driver.

The driver accepts 5V inputs, the output for the driver is up to 30V so you can connect an stepper motor of up to 30V if you use an external power supply. With the two push switches you can drive the stepper motor CW or CC or control it with a microcontroller

Hardware

The hardware consist of the AT2313 microcontroller which drives the ULN2003 driver and two push buttons to control the direction.

For more detail:  Stepper motor driver

This free embedded project also found using:

• stepper drivers atmga pdf
• 5V Stepper motor with atmega32 with diy driver circuit