Arduino_Blink

/*
  Blink
  Turns on an LED on for one second, then off for one second, repeatedly.
 
  This example code is in the public domain.
 */

// Pin 13 has an LED connected on most Arduino boards:
int led1 = 13;
// Pin 10 has an LED connected on most Arduino boards:
int led2 = 10;

void setup() {                
  // initialize the digital pin as an output.
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
}

void loop() {
  digitalWrite(led1, HIGH);   // set the LED1 on
  digitalWrite(led2, LOW);    // set the LED2 off
  delay(1000);              // wait for a second
  digitalWrite(led1, LOW);    // set the LED1 off
  digitalWrite(led2, HIGH);   // set the LED2 on
  delay(1000);              // wait for a second
}