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Controlling Motors & Servos with Arduino (Beginner’s Guide + Example Code)

Introduction

Blinking LEDs and reading sensors is fun… but nothing says “I’m really building robots” like controlling motors with Arduino. 💡

In this guide you’ll learn how to control:

  • ⚡ DC motors (for fans, wheels)
  • 🎚 Servo motors (for precise angles like robot arms)
  • 🔄 Stepper motors (for exact step movements like 3D printers)

We’ll go through wiring basics and ready‑to‑use Arduino code for each.

  1. Controlling a DC Motor with Arduino

A DC motor spins continuously when powered. Arduino itself can’t handle the high current, so we use a transistor or motor driver (L293D / L298N).

Wiring (transistor method):

  • Motor + external 5–9V supply
  • NPN transistor as a switch (TIP120 or 2N2222)
  • Motor + diode for back‑EMF protection
  • Arduino pin 9 → transistor base

Code (DC Motor On/Off):

C++

int motorPin = 9;

 

void setup() {

pinMode(motorPin, OUTPUT);

}

 

void loop() {

digitalWrite(motorPin, HIGH);  // Motor ON

delay(2000);

digitalWrite(motorPin, LOW);   // Motor OFF

delay(2000);

}

⚡ Motor spins 2s, stops 2s, repeats.

Code (DC Motor Speed Control with PWM):

C++

int motorPin = 9;  // PWM pin

 

void setup() {

pinMode(motorPin, OUTPUT);

}

 

void loop() {

for (int speed = 0; speed <= 255; speed += 5) {

analogWrite(motorPin, speed);   // Increase speed

delay(50);

}

for (int speed = 255; speed >= 0; speed -= 5) {

analogWrite(motorPin, speed);   // Decrease speed

delay(50);

}

}

💡 Motor gradually speeds up, then slows down.

  1. Controlling a Stepper Motor with Arduino

A stepper motor moves in exact steps (e.g., 200 steps per revolution). Great for 3D printers, CNC machines, precision robots.

We use ULN2003 or A4988 drivers.

Wiring: Stepper → ULN2003 board → Arduino pins 8, 9, 10, 11.

Code (Stepper Sweep):

C++

#include <Stepper.h>

 

const int stepsPerRevolution = 200;  // Motor depends, check datasheet

Stepper myStepper(stepsPerRevolution, 8, 9, 10, 11);

 

void setup() {

myStepper.setSpeed(60);  // 60 RPM

}

 

void loop() {

myStepper.step(stepsPerRevolution);    // One revolution

delay(1000);

myStepper.step(-stepsPerRevolution);   // Backwards

delay(1000);

}

🔄 Motor turns one full revolution clockwise, pauses, then counterclockwise.

FAQs

Q: Can I power a motor directly from Arduino pins?
A: No! Use a transistor or motor driver (like L293D or L298N).

Q: Why is my servo motor vibrating instead of moving?
A: Not enough stable power—use a 5V regulator or external supply.

Q: Can Arduino control multiple motors?
A: Yes! Use multi‑channel motor drivers or multiple PWM pins.

Ideas for Projects with Motors

  • Smart fan (DC motor + temperature sensor).
  • Robotic arm (servo motors).
  • Line follower robot (DC motors + motor driver).
  • 3D printer + CNC basics (stepper motors).

Conclusion

With DC, Servo, and Stepper motors, Arduino projects level up from blinking lights to real, moving robots.

  • DC = simple spin & speed
  • Servo = precise angles
  • Stepper = exact steps/revolutions

Once you combine sensors + motors: welcome to the world of actual robotics.