const int RED_LED = 4;
const int YELLOW_LED = 3;
const int GREEN_LED = 2;
const int SIG_GND = 5;

void setup() {
  pinMode(RED_LED, OUTPUT);
  pinMode(YELLOW_LED, OUTPUT);
  pinMode(GREEN_LED, OUTPUT);
  pinMode(SIG_GND, OUTPUT);

  Serial1.begin(115200);
  Serial1.println("Что видет водитель");
}

void loop() {
  // Красный
  digitalWrite(RED_LED, HIGH);
  digitalWrite(YELLOW_LED, LOW);
  digitalWrite(GREEN_LED, LOW);
  digitalWrite(SIG_GND, LOW);
  Serial1.println("СТОП");
  delay(6000);

  // Жёлтый
  digitalWrite(RED_LED, LOW);
  digitalWrite(YELLOW_LED, HIGH);
  digitalWrite(GREEN_LED, LOW);
  digitalWrite(SIG_GND, LOW);
  Serial1.println("ВНИМАНИЕ");
  delay(3000);

  // Зелёный
  digitalWrite(RED_LED, LOW);
  digitalWrite(YELLOW_LED, LOW);
  digitalWrite(GREEN_LED, HIGH);
  digitalWrite(SIG_GND, LOW);
  Serial1.println("СТАРТ");
  delay(6000);

  // Жёлтый
  digitalWrite(RED_LED, LOW);
  digitalWrite(YELLOW_LED, HIGH);
  digitalWrite(GREEN_LED, LOW);
  digitalWrite(SIG_GND, LOW);
  Serial1.println("ВНИМАНИЕ");
  delay(3000);
}