void setup() {

pinMode(15,OUTPUT);
pinMode(2,OUTPUT);
pinMode(4,OUTPUT);
}

void loop() {
 
digitalWrite(15,1); //vermelho
digitalWrite(2,0);
digitalWrite(4,0);
delay(4000);

digitalWrite(15,0); 
digitalWrite(2,1); //amarelo
digitalWrite(4,0);
delay(1500);

digitalWrite(15,0); 
digitalWrite(2,0);
digitalWrite(4,1); //verde
delay(4000);

}