Fritzing

A arduino project of simple Traffic Light System Without Button

Green is connected to pin 0

Yellow is connected to pin 2

Red is connected to pin 4

here is the Arduino code you will  need:

int LedRed = 4;
int LedYellow = 2;
int LedGreen = 0;

void setup(){
pinMode(LedRed, OUTPUT);
pinMode(LedYellow, OUTPUT);
pinMode(LedGreen, OUTPUT);
}

void loop(){
  digitalWrite(LedRed, LOW);
  digitalWrite(LedYellow, LOW);
  digitalWrite(LedGreen, HIGH);
  delay(3000);
  digitalWrite(LedYellow, HIGH);
  digitalWrite(LedGreen, LOW);
  delay(2000);
  digitalWrite(LedYellow, LOW);
  digitalWrite(LedRed, HIGH);
  delay(3000);
  digitalWrite(LedYellow, HIGH);
  delay(2000);
}