//
// Fading LED
//  

int value = 0;                             // variable to keep the actual value 
int ledpin1 = 9;                           // LED connected to pwm pin 9 via 1K ohm resistor
                                           // LED cathode connected to ground
void setup() 
{ 
  // nothing for setup 
} 
 
void loop() 
{ 
  
  //+++++++++
  // ramp up LED
  //+++++++++
  
  for(value = 0 ; value <= 255; value+=5)      // ramp the number in "value" from 0 to 255
  { 
    analogWrite(ledpin1, value);               // increase the voltage on pin 9 from 0 to 5 volts
    delay(30);                                 // waits for 30 milli seconds to see the dimming effect 
  }
  
  //+++++++++
  // ramp down LED
  //+++++++++
  
  for(value = 255; value >=0; value-=5)       // ramp the number in "value" from 255 to 0
  { 
    analogWrite(ledpin1, value);              // decrease the voltage on pin 9 from 5 to 0 volts 
    delay(30);                                // waits for 30 milli seconds to see the dimming effect 
  }   
}