const int trigPin = 14;
const int echoPin = 13;
const int ledPin = 4;

long duration, distance;
boolean isPaused = false;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  if (!isPaused) {
    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);
    duration = pulseIn(echoPin, HIGH);
    distance = duration * 0.034 / 2;
  
    if (distance < 30) {
      isPaused = true;
      digitalWrite(ledPin, HIGH);
    } else {
      digitalWrite(ledPin, LOW);
      delay(5000);
      digitalWrite(ledPin, HIGH);
    }
  } else {
    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);
    duration = pulseIn(echoPin, HIGH);
    distance = duration * 0.034 / 2;
  
    if (distance < 30) {
      digitalWrite(ledPin, HIGH);
    } else {
      digitalWrite(ledPin, LOW);
      isPaused = false;
      delay(5000);
      digitalWrite(ledPin, HIGH);
    }
  }
}