#define ECHO 18
#define TRIG 5 

#define GREEN_LED 13
#define YELLOW_LED 14
#define RED_LED 33


#define ECHO 18
#define TRIG 5 

#define GREEN_LED 27
#define YELLOW_LED 14
#define RED_LED 33

float duration;
int distance; 

void setup() {
  pinMode(TRIG, OUTPUT);
  pinMode(ECHO, INPUT);
  pinMode(GREEN_LED, OUTPUT);
  pinMode(YELLOW_LED, OUTPUT);
  pinMode(RED_LED, OUTPUT);

  Serial.begin(9600);
}

void loop() {
  digitalWrite(TRIG, LOW);
  delayMicroseconds(5);
  digitalWrite(TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG, LOW);

  duration = pulseIn(ECHO, HIGH);
  distance = duration * 0.0344 / 2;

  Serial.print(distance);
  Serial.println(" cm");
  delay(100);

  if (distance > 200) {
    digitalWrite(GREEN_LED, HIGH);
    digitalWrite(YELLOW_LED, LOW);
    digitalWrite(RED_LED, LOW);
  } else if (distance >= 100 && distance <= 199) {
    digitalWrite(GREEN_LED, LOW);
    digitalWrite(YELLOW_LED, HIGH);
    digitalWrite(RED_LED, LOW);
  } else {
    digitalWrite(GREEN_LED, LOW);
    digitalWrite(YELLOW_LED, LOW);
    digitalWrite(RED_LED, HIGH);
  }
}