Ultimate Guide to Servo Motors: SG90 & MG995 with Arduino

Introduction

Servo motors are the muscles of robotics. Unlike normal DC motors that spin continuously, a Servo Motor can rotate to a specific angle (usually 0 to 180 degrees). This makes them perfect for:

• Robotic Arms
• RC Plane rudders
• Automatic Door locks
• Camera gimbals

In this guide, we will learn how to control them using an Arduino Uno.

Choosing Your Motor

Which one do you need?

1. SG90 Micro Servo (Plastic Gear): Small, cheap, and lightweight. Perfect for small sensors or light mechanisms.
2. MG995 Metal Gear Servo: Heavy-duty, high torque (10kg/cm). Best for robotic arms and walking robots.

Wiring Diagram

Servos usually have 3 wires. Connecting them wrong can damage your board, so be careful!

• Brown or Black Wire: Connect to GND (Ground).
• Red Wire: Connect to 5V.
• Orange or Yellow Wire: Connect to Digital Pin 9 (PWM).

Warning for MG995 Users: The Arduino 5V pin can handle one small SG90. But if you are using the big MG995 or multiple servos, you MUST use an external battery (like a Lipo Battery) to power the motors. Just remember to connect the battery GND to Arduino GND.

The Code

Arduino makes controlling servos incredibly easy with the <Servo.h> library. Copy this code into your Arduino IDE:

#include <Servo.h>

Servo myServo;  // Create a servo object to control the motor

void setup() {
  myServo.attach(9);  // Attaches the servo on Pin 9 to the servo object
}

void loop() {
  // Sweep from 0 to 180 degrees
  for (int pos = 0; pos <= 180; pos += 1) { 
    myServo.write(pos);              // Tell servo to go to position in variable 'pos'
    delay(15);                       // Wait 15ms for the servo to reach the position
  }
  
  // Sweep back from 180 to 0 degrees
  for (int pos = 180; pos >= 0; pos -= 1) { 
    myServo.write(pos);              
    delay(15);                       
  }
}