(:source http://github.com/arduino/Arduino/raw/master/build/shared/examples/03.Analog/Fading/Fading.ino lang=arduino tabwidth=4:)

(:source http://github.com/arduino/Arduino/raw/master/build/shared/examples/3.Analog/Fading/Fading.ino lang=arduino tabwidth=4:)

(:source http://github.com/arduino/Arduino/raw/new-extension/build/shared/examples/3.Analog/Fading/Fading.ino lang=arduino tabwidth=4:)

Fading

• analogWrite()

• for()
• analogWead?()

(:divend:)

See Also:

• pinMode()
• analogRead()
• digitalWrite()
• delay()

• AnalogReadSerial - read a potentiometer, print its state to the serial monitor
• AnalogInOutSerial - read an analog input, map its values, and then use that information to dim or brighten an LED.
• Fade - use an analog input to fade an LED
• Calibration - calibrating analog sensor readings

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.

(:source http://github.com/arduino/Arduino/raw/master/build/shared/examples/3.Analog/Fading/Fading.pde lang=arduino tabwidth=4:)

 (:source http://github.com/arduino/Arduino/raw/master/build/shared/examples/3.Analog/Fading/Fading.pde lang=arduino tabwidth=4:)

 (:source http://github.com/arduino/Arduino/raw/master/build/shared/examples/3.Analog/Fading/Fading.pde language=arduino tabwidth=4:)

 (:source http://github.com/arduino/Arduino/raw/master/build/shared/examples/Analog/Fading/Fading.pde language=arduino tabwidth=4:)

image developed using Fritzing. For more circuit examples, see the Fritzing project page

(:div class=code :)

 /*
  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 17 June 2009
  By Tom Igoe
  
  http://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);                            
   } 
 }

(:divend:)

Attach:Dimmer_schem2.png Δ Δ

Circuit

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

click the image to enlarge

Schematic

click the image to enlarge Attach:Dimmer_schem.png Δ Δ

/*

 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 17 June 2009
 By Tom Igoe

 http://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);                            
  } 

An LED connected to pin 9 through an appropriate resistor (here 270 ohms).

Demonstrates the use of analog output (PWM) to fade an LED.

An LED connected to digital pin 9.

Examples > Analog I/O

Fading

Circuit

Code

int value = 0;                            // variable to keep the actual value 
int ledpin = 9;                           // light connected to digital pin 9

void setup() 
{ 
  // nothing for setup 
} 

void loop() 
{ 
  for(value = 0 ; value <= 255; value+=5) // fade in (from min to max) 
  { 
    analogWrite(ledpin, value);           // sets the value (range from 0 to 255) 
    delay(30);                            // waits for 30 milli seconds to see the dimming effect 
  } 
  for(value = 255; value >=0; value-=5)   // fade out (from max to min) 
  { 
    analogWrite(ledpin, value); 
    delay(30); 
  }  
}