Unipolar Stepper Motor Drivers

There are actually many ways you can interface a stepper motor to your controller, out of them the most used interfaces are:

• Interface using L293D - H-Bridge Motor Drive
• Interface using ULN2003/2004 - Darlington Arrays

ULN2003/2003 Driver:

The below circuit is of unipolar stepper motor driver using uln2003. The "Controller pin 1",2,3 and 4 will control the motion and direction of the stepper motor according to the step sequence programmed in the controller.

Stepper Motor Driver

Two wire connection for unipolar stepper motor:

We have seen the generally used 4-wire connection method for interfacing unipolar stepper motor, but we can simplify the design to make controller use less pins with the help of 2-wire connection method. The circuit for 2-wire connection is shown below.

2-wire Stepper Motor Driver