/*
  Traffic_Signals
  Operates Red. Yellow & Green LED's as Traffic Signals
  
  This example code is in the public domain.
 */

// Pin 13 has an LED connected on most Arduino boards.
// give it a name:
int greenled = 8;
int yellowled = 9;
int redled = 10;

// the setup routine runs once when you press reset:
void setup() {
  // initialize the digital pin as an output.
  pinMode(greenled, OUTPUT);
  pinMode(yellowled, OUTPUT);
  pinMode(redled, OUTPUT);
}

// the loop routine runs over and over again forever:
void loop() {
  digitalWrite(redled, LOW);     // turn off red LED
  digitalWrite(yellowled, LOW);  // turn off yellow LED  
  digitalWrite(greenled, HIGH);  // turn on green LED (HIGH is the voltage level)
  delay(10000);                  // green LED for 15 seconds
  digitalWrite(greenled, LOW);   // turn off green LED by making the voltage LOW
  digitalWrite(yellowled, HIGH); // turn on yellow LED
  delay(2500);                   // wait 5 seconds
  digitalWrite(yellowled, LOW);  // turn off yellow LED
  digitalWrite(redled, HIGH);    // turn on red LED
  delay (10000);                 // wait 15 secongs
}