Stepper Motor Controller Using Arduino

Project Report: Arduino-Based Stepper Motor Controller

1. Introduction

This project outlines the development of a microcontroller-driven stepper motor controller using an Arduino Uno, ULN2003 driver IC, push buttons for direction control, a variable resistor for speed adjustment, and a 5V DC power supply. Stepper motors offer precise control over angular positioning, making them suitable for various applications such as robotics, 3D printing, and CNC machines. This project provides a fundamental framework for controlling a stepper motor using Arduino’s digital output pins.

2. Components

• Arduino Uno (or compatible board)
• ULN2003 stepper motor driver IC
• Stepper motor (compatible with ULN2003 driver current rating)
• 2 Push buttons (momentary)
• 10kΩ Variable resistor (potentiometer)
• Jumper wires
• Breadboard (optional)

5V DC power supply (current rating based on stepper motor requirements

3. Circuit Design
4. Connect the ULN2003’s VCC pin to the Arduino’s 5V pin.
5. Connect the ULN2003’s GND pin to the Arduino’s GND pin.
6. Connect the Arduino’s digital output pins (e.g., pins 8, 9, 10, and 11) to the ULN2003’s input pins (IN1, IN2, IN3, and IN4).
7. Connect the stepper motor’s coils to the ULN2003’s output pins (OUT1, OUT2, OUT3, and OUT4). Ensure proper coil connection sequence based on your motor’s datasheet.
8. Connect one push button (e.g., normally open) between a digital pin (e.g., pin 2) and ground (with a pull-up resistor if needed) for clockwise control.
9. Connect the other push button (normally open) between another digital pin (e.g., pin 3) and ground (with a pull-up resistor if needed) for counterclockwise control.
10. Connect one end of the variable resistor to the Arduino’s 5V pin, the other end to ground, and the wiper (middle pin) to an analog input pin (e.g., pin A0).
11. Connect the 5V DC power supply’s positive terminal to the Arduino’s Vin or external power supply pin (if applicable) and the negative terminal to ground. Double-check the voltage and current requirements of your stepper motor to ensure compatibility with the power supply.

4. Code

The Arduino code controls the stepper motor direction and speed based on push button presses and the variable resistor value. Here’s a basic example:

C++

#define CW_PIN 2  // Clockwise push button pin
#define CCW_PIN 3 // Counterclockwise push button pin
#define SPEED_PIN A0  // Variable resistor (speed control) pin

const int motorPins[4] = {8, 9, 10, 11}; // ULN2003 input pins

int step = 0;      // Current step position
int direction = 0; // 0 for clockwise, 1 for counterclockwise
int speed = 0;     // Speed value from variable resistor

void setup() {
  pinMode(CW_PIN, INPUT_PULLUP);
  pinMode(CCW_PIN, INPUT_PULLUP);
  pinMode(SPEED_PIN, INPUT);

  for (int i = 0; i < 4; i++) {
    pinMode(motorPins[i], OUTPUT);
  }
}

void loop() {
  // Read push button states
  int cwPressed = !digitalRead(CW_PIN);
  int ccwPressed = !digitalRead(CCW_PIN);

  // Update direction based on button presses
  if (cwPressed) {
    direction = 0;
  } else if (ccwPressed) {
    direction = 1;
  }

  // Read speed value from variable resistor
  speed = map(analogRead(SPEED_PIN), 0, 1023, 0, 255);

  // Stepper motor control logic (replace with your desired stepping sequence)
  stepMotor(direction, speed);
}

void stepMotor(int dir, int spd) {
  // Implement your stepper motor stepping
}