switch by BARRAGAN http://barraganstudio.com

Demonstrates the use of digital pins and a switch. The pin used as input is connected to a switch and the pin used as output is the onboard LED When the switch is pressed, the light blinks, the light goes off when the switch is released.

int direction = 1;  // used for the blinking cycle
int switchPin = 0;  // digital pin to attach the switch
int ledPin = 48;    // Wiring onboard LED 


void setup() 
{
  pinMode(switchPin, INPUT);  // sets digital pin 0 as input
  pinMode(ledPin, OUTPUT);    // sets digital pin 48 as output
}

void loop() 
{
  if(digitalRead(switchPin) == HIGH)  // if the switch is pressed 
  {
    direction *= -1;                  // alternate between 1 or -1
    if (direction == 1)               // to decide to turn on or off the light
    {
      digitalWrite(ledPin, HIGH);     // turns the light on
    }
    else                              
    {
      digitalWrite(ledPin, LOW);      // turns the light off
    }
    delay(200);                       // wait 200 milliseconds
  }
  else                                // if switch not pressed
  {
    digitalWrite(ledPin, LOW);        // keeps the light off
  }
}