How to Use Servo Library in Arduino: Simple Guide

To use the Servo library in Arduino, first include it with #include <Servo.h>, then create a Servo object. Attach the servo to a pin using attach() and control its angle with write().

Syntax

The basic syntax to use the Servo library involves including the library, creating a Servo object, attaching it to a pin, and setting the servo angle.

• #include <Servo.h>: Adds the Servo library to your sketch.
• Servo servoName;: Creates a servo object to control one servo.
• servoName.attach(pin);: Connects the servo object to a specific Arduino pin.
• servoName.write(angle);: Moves the servo to the specified angle (0 to 180 degrees).

arduino

#include <Servo.h>

Servo myServo;  // Create servo object

void setup() {
  myServo.attach(9);  // Attach servo to pin 9
}

void loop() {
  myServo.write(90);  // Move servo to 90 degrees
  delay(1000);       // Wait 1 second
}

Example

This example shows how to sweep a servo motor back and forth between 0 and 180 degrees smoothly.

arduino

#include <Servo.h>

Servo myServo;

void setup() {
  myServo.attach(9);  // Attach servo to pin 9
}

void loop() {
  for (int angle = 0; angle <= 180; angle += 1) {
    myServo.write(angle);  // Move servo to angle
    delay(15);             // Wait for servo to reach position
  }
  for (int angle = 180; angle >= 0; angle -= 1) {
    myServo.write(angle);
    delay(15);
  }
}

Output

Servo motor moves smoothly from 0° to 180° and back repeatedly.

Common Pitfalls

Common mistakes when using the Servo library include:

• Not calling attach() before write(), which means the servo won't move.
• Using pins that do not support PWM or servo control (usually pins 9 and 10 are safe).
• Trying to control multiple servos without enough power supply, causing erratic behavior.
• Setting angles outside 0-180 degrees, which can damage the servo.

arduino

// Wrong: Writing angle before attaching servo
#include <Servo.h>
Servo myServo;
void setup() {
  myServo.write(90);  // Wrong: servo not attached yet
  myServo.attach(9);
}
void loop() {}

// Right:
#include <Servo.h>
Servo myServo;
void setup() {
  myServo.attach(9);  // Attach first
  myServo.write(90);  // Then write angle
}
void loop() {}

Quick Reference

Function	Description
#include	Include the Servo library
Servo servoName;	Create a servo object
servoName.attach(pin);	Attach servo to Arduino pin
servoName.write(angle);	Set servo angle (0-180 degrees)
servoName.detach();	Release the servo control

Key Takeaways

Always include #include <Servo.h> and create a Servo object before use.

Attach the servo to a pin with attach() before sending angle commands.

Use write() to set the servo angle between 0 and 180 degrees safely.

Avoid controlling servos on unsupported pins or without sufficient power.

Detach servos with detach() when no longer controlling them to save power.