Tiny Stepper

Arduino library to drive stepper motors. Small and easy to use.

Description

Simple library to drive a 4-phase stepper motor using simple Move(), AccelMove() and Disable() functions. Works well with 28BYJ-48 stepper motor and UNL2003 module. Focus is on controlling steppers with basic Move(x) commands where x is positive or negative value (in degrees). Uses half-step for more torque and smoother motion.

Hardware

A Stepper Motor is typically driven by a ULN2003A which provides an array of seven NPN Darlington transistors capable of 500 mA, 50 V output, great for driving inductive loads like a motor.

The stepper motor has 4 different position coils, ABCD. In half step mode, you energize the adjacent coil before disengaging the previous coil. The transition steps would be these 8 patterns: A, AB, B, BC, C, CD, D, DA:

  Phase ABCD Coils
  0     1000  A
  1     1100  AB
  2     0100   B
  3     0110   BC
  4     0010    C
  5     0011    CD
  6     0001     D
  7     1001  A  D

The ABCD coils map to IN1, IN2, IN3, and IN4 that will be connected to the Arduino digital outputs.

Power Note: You should not drive the stepper motor power with the Arduino. The power to the UNL2003 module should come from the main power adapter that also feeds the Arduino.

Installation

This library is available via the Arduino IDE. Install this library via Tools, Manage Libraries, search for "TinyStepper" and click Install.

You can also install the latest version manually by cloning this repo into your Arduino library folder (e.g. ~/Documents/Arduino/libraries).

Usage

The library provides a single class named TinyStepper with the following functions:

• Move - Move the stepper motor specified in degrees (positive or negative)
• AccelMove - Move the stepper motor specified in degrees but accelerate and decelerate.
• Enable - Enable/lock the stepper motor
• Disable - Disable/unlock the stepper motor (free spin)

Example Code

#include <TinyStepper.h>

// Define Arduino Pin Outputs
#define IN1 8
#define IN2 9
#define IN3 10
#define IN4 11
#define HALFSTEPS 4096  // Number of half-steps for a full rotation

// Init the TinyStepper Class
TinyStepper stepper(HALFSTEPS, IN1, IN2, IN3, IN4);

void setup()
{
  Serial.begin(38400);
  stepper.Enable();
  delay(1000);
}

void loop() {
  // Random back and forth
  Serial.println("Random Test");
  stepper.Move(45);
  stepper.Move(-90);
  stepper.Move(120);
  stepper.Move(-15);
  stepper.Move(30);
  stepper.Move(-300);
  stepper.Move(600);
  stepper.Move(-100);
  delay(2000);

  // Accelerate/decelerate 360 full rotation - both directions
  Serial.println("Full Rotation");
  stepper.AccelMove(360);
  stepper.AccelMove(-360, 1, 10);
  delay(2000);
}

Refer to TinyStepper.h for information on available functions. See also Examples for more demonstration.