ULN2003 Stepper Motor Driver (UNIPOLAR)
ULN2003 Stepper Motor Driver Board uses ULN2003 DARLINGTON ARRAYS to drive a 4-phase 5-wire UNIPOLAR stepper motor (5v-12v).
Module Type: Driver
Board Size 4cm x 2.1cm
Operation Level Digital: 5V
Power Supply External: 5-12V
Arduino has a built-in Stepper Library with information regarding UNIPOLAR and BIPOLAR Stepper Motors.
Tom Igoe has some good notes regarding Steppers.