A Quick Guide to Servo Motors

Servo motors use feedback to determine it’s position, therefore they can be used to control the position of objects, rotate objects,various parts of a robot with high precision. The size of a servo motor is considerably small and with their built in circuitry, they can be connected directly to a micro-controller.           Servo motors were first used in the Remote Control (RC) world, usually to control the steering of RC cars or the flaps on a RC plane. With time, they found their uses in robotics, automation, and of course, the Arduino world In this article, we’ll look at how to interface a servo motor with an Arduino UNO micro-controller.

SG-90 servo motor
SG-90 servo motor
Servo pwm
Servo pwm

Most servos you’ll see around have three connections

  • Black/Brown – ground wire
  • Red – +Ve wire
  • Orange/Yellow/White – signal wire

Servo motors run on 5V, so it can be powered directly from your Arduino 5V port.

You’ll need the following to carry out this project

Hardware

  • 1 x SG-90 servo motor here
  • 1 x Arduino UNO, buy here

Software

  • Arduino IDE, download here

Step 1: Circuitry

Arduino servo motor circuit
Arduino servo motor circuit

Step 2: Upload the code

Fire up your Arduino IDE and follow the instructions below

  • Click on File
  • Go to Examples
  • Select servo, Sweep
  • Or you can copy the code below
  • Click on upload
/* Sweep
 by BARRAGAN <http://barraganstudio.com>
 This example code is in the public domain.

 modified 8 Nov 2013
 by Scott Fitzgerald
 http://www.arduino.cc/en/Tutorial/Sweep
*/

#include <Servo.h>

Servo myservo; // create servo object to control a servo
// twelve servo objects can be created on most boards

int pos = 0; // variable to store the servo position

void setup() {
 myservo.attach(9); // attaches the servo on pin 9 to the servo object
}

void loop() 
{
 for (pos = 0; pos <= 180; pos += 1)
 { // goes from 0 degrees to 180 degrees
 // in steps of 1 degree
 myservo.write(pos); // tell servo to go to position in variable 'pos'
 delay(15); // waits 15ms for the servo to reach the position
 }
 for (pos = 180; pos >= 0; pos -= 1) 
 { // goes from 180 degrees to 0 degrees
 myservo.write(pos); // tell servo to go to position in variable 'pos'
 delay(15); // waits 15ms for the servo to reach the position
 }
}

Results

If you did everything right, your servo motor should rotate 180 degrees in a clockwise motion and vice versa

Arduino servo result
Arduino servo result

Wanna do more????

You could build a Bluetooth mobile phone controlled R.C car

Extra part needed

  • 2WD motor kit, buy it here

Refer to this article on interfacing a HC-05/HC-06 Bluetooth module with your mobile phone.

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