View source for Experiment 7: Stepper Motor Control via Microcontroller

= Experiment 7: Stepper Motor Control via Microcontroller =

== Objective ==
To control the rotation and direction of a stepper motor using Arduino and a ULN2003 driver.

== Task ==
# Connect stepper motor and driver to Arduino.  
# Write code to rotate motor clockwise and counter-clockwise.  
# Vary delay to change motor speed.  

=== Circuit Diagram ===
[[File:Eecit-kit-07-circuit.png|center|thumb|400px|Circuit Diagram]]

=== Board Connections ===
[[File:Eecit-kit-07-board-connection.png|center|thumb|400px|Board Connections]]

== Connections ==
{| class="wikitable" style="text-align:center;"
! Component !! Arduino Pin !! Description
|-
| Stepper Motor IN1 || D8  || Control input 1
|-
| Stepper Motor IN2 || D10 || Control input 2
|-
| Stepper Motor IN3 || D9  || Control input 3
|-
| Stepper Motor IN4 || D11 || Control input 4
|-
| ULN2003 VCC || 5V || Power supply for driver
|-
| ULN2003 GND || GND || Common ground
|}

== Code ==
<pre>
// © 2025, Cognifront. Member of The IoT Kits Family.

//Experiment 7: Stepper Motor Control via Microcontroller

// Include the Stepper motor library
#include <Stepper.h>

// Define the number of steps per revolution for the stepper motor
// For a 28BYJ-48 stepper, it's typically 2048 steps per revolution (with gear reduction)
const int stepsPerRevolution = 2048;  

// Create a Stepper object named myStepper
// Connected to digital pins 8, 10, 9, 11 (sequence matters!)
Stepper myStepper(stepsPerRevolution, 8, 10, 9, 11);

void setup() {
  // Start serial communication for debugging and monitoring
  Serial.begin(9600);
  Serial.println("Stepper Motor Speed Test"); // Initial message
}

void loop() {
  // Rotate clockwise (CW) at increasing speeds
  for (int spd = 5; spd <= 20; spd += 5) {
    Serial.print("Rotating CW at ");
    Serial.print(spd);
    Serial.println(" RPM");

    myStepper.setSpeed(spd);                        // Set stepper speed in RPM
    myStepper.step(stepsPerRevolution / 2);         // Rotate 1/2 revolution in CW direction
    delay(500);                                     // Short pause between speed changes
  }

  // Rotate counterclockwise (CCW) at decreasing speeds
  for (int spd = 20; spd >= 5; spd -= 5) {
    Serial.print("Rotating CCW at ");
    Serial.print(spd);
    Serial.println(" RPM");

    myStepper.setSpeed(spd);                        // Set stepper speed in RPM
    myStepper.step(-stepsPerRevolution / 2);        // Rotate 1/2 revolution in CCW direction
    delay(500);                                     // Short pause between speed changes
  }
}
</pre>

== Observation ==
* The stepper motor rotates in both clockwise and counterclockwise directions.  
* The motor speed changes as per the programmed RPM values.  
* Smooth operation is observed with correct wiring sequence.  

== Conclusion ==
The experiment successfully demonstrates control of a stepper motor’s speed and direction using Arduino and a ULN2003 driver. This forms the basis for applications like robotic motion control, CNC systems, and precise positioning mechanisms.