const int trigPin = D10; // Trigger
const int echoPin = D9; // Echo
const int LED = D7;
long duration, cm;

void setup() {
  // Start the Serial Port
  Serial.begin(9600);
  
  Serial.println("Serial communication started.");

  // Define pin modes
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(LED, OUTPUT);
}

void loop() {
  // Ensure a clean HIGH pulse
  digitalWrite(trigPin, LOW);
  delayMicroseconds(5);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read the signal from the sensor
  duration = pulseIn(echoPin, HIGH);

  // Convert the time into a distance
  cm = (duration / 2.0) / 29.1;

  // Print the distance to the Serial Monitor
  Serial.print("Distance: ");
  Serial.print(cm);
  Serial.println(" cm");

  // Control the LED based on the distance
  if (cm < 10) {
    digitalWrite(LED, HIGH);
  } else {
    digitalWrite(LED, LOW);
  }

  // Short delay before the next measurement
  delay(250);
}