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Reference

Stepper Library

The Stepper library allows you to connect stepper motors, which move in small individual steps that makes slow and precise movement easy.

Download: Stepper is included with Arduino

Hardware Requirements

Stepper is compatible with all Teensy boards. Stepper can control unipolar or bipolar stepper motors. In this photo, Stepper is controlling a unipolar stepper motor salvaged from an old Teac 5¼ inch floppy disk drive.

Small stepper motors designed for 5 volts may be able to run from power provided by USB. Larger motors will require separate power.

Basic Usage

Stepper mystepper(steps, pin1, pin2, pin3, pin4);

Create an instance of the Stepper library for a unipolar type stepper motor. You will need to create an instance for each motor, giving each motor a unique name of your choice.

Stepper mystepper(steps, pin1, pin2);

Create an instance of the Stepper library for a bipolar type stepper motor.

Movement Control

mystepper.setSpeed(rpm);

Sets the speed, in rotations per minute.

mystepper.step(number);

Move the motor 1 or more steps. The number can be positive or negative, to specify the direction of movement.

Example Program

This example is a slightly modified version of MotorKnob, which can be opened from the File -> Examples -> Stepper menu.

/*  MotorKnob - slightly modified
 *
 * A stepper motor follows the turns of a potentiometer
 * (or other sensor) on analog input 0.
 */

#include <Stepper.h>

// the number of steps on your motor
#define STEPS 200

// create an instance of the stepper class, specifying
// the number of steps of the motor and the pins it's
// attached to
Stepper stepper(STEPS, 7, 9, 8, 10);

// the previous reading from the analog input
long previous = STEPS / 2;

void setup()
{
  // set the speed of the motor to 30 RPMs
  stepper.setSpeed(30);
}

void loop()
{
  // get the sensor value.  This equation maps the
  // analogRead range to the number of steps, so the
  // motor nicely tracks a potentiometer's position
  long val = (long)analogRead(0) * STEPS / 1024;

  // move a number of steps equal to the change in the
  // sensor reading
  stepper.step(val - previous);

  // remember the previous value of the sensor
  previous = val;
}

Unipolar Stepper Motors

TODO: info about unipolar type motors

TODO: schematic for circuit in photo above (2N3904 transistors, 1N4936 diodes, 1K resistors)

TODO: how to identify the common wire using a multimeter, and trial-error to get the windings sorted out

Bipolar Stepper Motors

TODO: info about bipolar type motors

TODO: suggested schematic using an "easy" H-bridge chip

TODO: how to identify each winding usine a multimeter

More Details

Please refer to the official Stepper library documentation for more details.