Fading.md

title	compatible-products	difficulty	description	tags	featuredImage
Fading	all-boards	intermediate	Use an analog output (PWM pin) to fade an LED.	Analog Output LED PWM	led

This example demonstrates the use of analog output (Pulse Width Modulation (PWM)) to fade an LED. PWM is a technique for getting an analog-like behavior from a digital output by switching it off and on very fast and with different ratio between on and off time.

Hardware Required

• Arduino Board

• LED

• 220 ohm resistor

• hook-up wires

• breadboard

Circuit

An LED connected to digital output pin 9 through a 220 ohm resistor.

Schematic

Code

In this example two loops are executed one after the other to increase and then decrease the value of the output on pin 9.

/*

  Fading

  This example shows how to fade an LED using the analogWrite() function.

  The circuit:

  - LED attached from digital pin 9 to ground.

  created 1 Nov 2008

  by David A. Mellis

  modified 30 Aug 2011

  by Tom Igoe

  This example code is in the public domain.

  https://www.arduino.cc/en/Tutorial/Fading

*/

int ledPin = 9;    // LED connected to digital pin 9

void setup() {

  // nothing happens in setup
}

void loop() {

  // fade in from min to max in increments of 5 points:

  for (int fadeValue = 0 ; fadeValue <= 255; fadeValue += 5) {

    // sets the value (range from 0 to 255):

    analogWrite(ledPin, fadeValue);

    // wait for 30 milliseconds to see the dimming effect

    delay(30);

  }

  // fade out from max to min in increments of 5 points:

  for (int fadeValue = 255 ; fadeValue >= 0; fadeValue -= 5) {

    // sets the value (range from 0 to 255):

    analogWrite(ledPin, fadeValue);

    // wait for 30 milliseconds to see the dimming effect

    delay(30);

  }
}

Learn more

You can find more basic tutorials in the built-in examples section.

You can also explore the language reference, a detailed collection of the Arduino programming language.

Last revision 2015/07/29 by SM