Arduino Analog Output – LED fade in and fade out.

This tutorial explains how to take analog output from Arduino. One of the basic tutorials for Arduino. The output is taken on a LED that fades in and fades out. The video of output is also included.

1. Introduction:

A step by step illustrated very basic tutorial for Arduino. Here we are taking analog output on a LED. This LED gets fade in and then fade out.

Arduino gives analog output in range of 0 to 255. Technically the output is digital but in the form of PWM, but it seems to be analog.

Arduino Boards have 6 PWM(Analog Pins) these are PIN No. 3,5,6,9,10,11.

This tutorial is made on Original Arduino UNO and Robo India’s R-Board(UNO compatible.)

2. Required Hardware

Following Hardware will be required to perform this LED fade in and fade out circuit.

S.No.	Item	Quantity
1.	R-Board with FTDI or Arduino Board	1
2.	Bread Board	1
3.	Male to male Jumpers	4
4.	Indicator LED	1
5.	100 OHM Resistance	1

3. Building Circuit

Make following circuit with the help of above mentioned components.

3.1 You may go with Robo India’s R-Board ( UNO Compatible)-

• 

Here is the schematic of this circuit-

• 

or

3.2 You may go with original Arduino UNO Board-

• 

Here is the schematic of this circuit-

• 

4. Programming:

Once we are done with circuit part, here is our programme to this circuit.

You may download this code (Arduino Sketch) from here.

/*
Tutorial for Analog Output. 
Analog output is taken through PWM.
Prepared by Robo India.
www.roboindia.com
 */

int LED_ao = 3; // The LED attached to Pin 3 for analog output.           

void setup()  { 
   
  pinMode(LED_ao, OUTPUT); // Declaring Pin as output.
} 

 
void loop()  { 
 // Range of PWM is 0 to 255. So we are running FOR LOOP for 1 to 255.
  for (int brightness=1; brightness<=255; brightness++)  // For loop for Fade In effect.
    {
      analogWrite(LED_ao, brightness);  // LED will glow for value of 1 to 255.
      delay(20);                     // Small delay to see fade effect.      
    }
  for (int brightness=255; brightness>0; brightness--) // Same FOR LOOP for Fade out effect.
    {
      analogWrite(LED_ao, brightness);  
      delay(20);     
    }


                           
}

 5. output:

Here is the output of this tutorial-

 6. You may Download Arduino Code (Sketch) of exercise-2 shown in above video.

If you have any query please write us at support@roboindia.com

Thanks and Regards
Content Development Team 
Robo India
http://roboindia.com