const int trigPin = 9;
const int echoPin = 10;

const int ledPin = 13;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(ledPin, OUTPUT);
  Serial.begin(300);
}

void loop() {
  // Trigger a pulse
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read echo pulse duration
  long duration = pulseIn(echoPin, HIGH);

  // Convert duration to distance in cm
  float distance = duration * 0.034 / 2;

  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  // Check distance and control LED
  if (distance < 10.0) {
    digitalWrite(ledPin, HIGH); // Turn on LED
  } else {
    digitalWrite(ledPin, LOW);  // Turn off LED
  }

  delay(200); // small delay between readings
}