If you?re interested in robotics, motion control, or just want to learn about stepper motors, then you should try building this versatile stepper motor controller.

This project allows you to control the speed, direction, and step size of a unipolar four-phase stepper motor. The controller is capable of handling motor winding currents of up to 1.25 amps per phase and it operates from a single supply voltage of 6-30 volts DC. A unique feature f this project is that the circuit can operate in either remote mode or stand-alone mode. In the stand-alone mode, an on-board pulse generator and a four-position DIP switch allows you to demonstrate all of the functions without any additional connections. This mode is perfect for demonstrating basic stepper motor control principles. The circuit even has LEDs that show the energized phases for each step. In remote mode, all motor functions can be interfaced to external logic or a microcontroller. This allows the controller to be incorporated into a robot, an X-Y plotter, or any motion control project you have in mind!

CIRCUIT DESCRIPTION
Refer to the schematic of the stepper driver shown in Figure 1. Power is supplied by a DC wall transformer or DC power supply at P1. The voltage can be anything from 6 to 30 volts, depending upon the rating of the stepper motor. The stepper motor uses most of the current in this circuit, so it is powered directly from the transformer output through resistors R1 & R2. These resistors limit the current to the motor and allow the motor to be operated with a power supply voltage greater than the voltage rating of the motor for improved performance.

(more…)