No libraries required. arduino

// Define the pin numbers for the LEDs

const int redLed = 9;

const int yellowLed = 10;

const int greenLed = 11;

void setup() {

// Set the LED pins as output

pinMode(redLed, OUTPUT);

pinMode(yellowLed, OUTPUT);

pinMode(greenLed, OUTPUT);

} void loop() {

// Red light for 5 seconds

digitalWrite(redLed, HIGH);

delay(5000);

digitalWrite(redLed, LOW);

// Yellow light for 2 seconds digitalWrite(yellowLed, HIGH);

delay(2000);

digitalWrite(yellowLed, LOW);

// Green light for 5 seconds

digitalWrite(greenLed, HIGH);

delay(5000);

digitalWrite(greenLed, LOW);

}