6.4.1 Introduction

A servo motor is an actuator used to control angular position.

Unlike a simple DC motor, a servo motor can be commanded to move to a particular position.

Typical hobby servos can rotate through approximately 180°, although the actual range depends on the servo model.

6.4.2 Types of Servo Motors

Common types include:

1. Positional servo
2. Continuous rotation servo
3. Linear servo

Examples of hobby servos include:

• SG90
• MG90S
• MG996R

6.4.3 Components

A typical servo has:

• Power wire
• Ground wire
• Signal wire

Typical colors vary by manufacturer, so the labels or datasheet should be checked.

6.4.4 Working Principle

The Arduino sends a control signal to the servo.

The servo’s internal electronics and motor mechanism move the shaft toward the commanded position.

For a standard positional servo:

Arduino → Control Signal → Servo → Shaft Movement

6.4.5 Connection to Arduino

Example:

Servo	Arduino
Signal	D9
VCC	5V/external suitable supply
GND	GND

For larger servos, an external power supply may be required. The Arduino and external supply should share a common ground when appropriate.

6.4.6 Servo Library

Arduino provides the Servo library.

#include <Servo.h>

Important functions include:

• attach()
• write()
• detach()

6.4.7 Arduino Programming and Code

#include <Servo.h>

Servo myServo;

void setup() {

  myServo.attach(9);

}

void loop() {

  myServo.write(0);

  delay(1000);

  myServo.write(90);

  delay(1000);

  myServo.write(180);

  delay(1000);

}

6.4.8 Code Description

• Servo.h provides servo control functions.
• Servo myServo creates a servo object.
• attach(9) connects the servo signal to pin 9.
• write(0) moves the servo toward 0°.
• write(90) moves it toward 90°.
• write(180) moves it toward 180°.
• delay() provides time between movements.

6.4.9 Applications

Servo motors are used in:

• Robotic arms
• Automatic doors
• Camera positioning
• Robot steering
• Model systems
• Lock mechanisms
• Solar tracking systems