const int trigPin = 9;        // Trig pin of the transmitter sensor
const int echoPinReceiver = 10; // Echo pin of the receiver sensor
const int ledSender = 3;      // LED pin for the transmitter
const int ledReceiver = 7;    // LED pin for the receiver

void setup() {
  Serial.begin(9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPinReceiver, INPUT);
  pinMode(ledSender, OUTPUT);
  pinMode(ledReceiver, OUTPUT);
}

void loop() {
  // Send a pulse from the transmitter sensor
  Serial.println("Sender: Sending pulse...");
  digitalWrite(ledSender, HIGH);  // Turn on the sender LED
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  digitalWrite(ledSender, LOW);  // Turn off the sender LED

  // Read the pulse duration from the receiver sensor
  Serial.println("Receiver: Waiting for pulse...");
  long duration = pulseIn(echoPinReceiver, HIGH);

  // Calculate the distance (in cm)
  float distance = (duration * 0.0343) / 2.0;

  // Indicate reception and print the distance
  if (duration > 0) {
    digitalWrite(ledReceiver, HIGH);  // Turn on the receiver LED
    Serial.print("Receiver: Distance received: ");
    Serial.print(distance);
    Serial.println(" cm");
    delay(100);  // Keep the LED on for a short period
    digitalWrite(ledReceiver, LOW);  // Turn off the receiver LED
  } else {
    Serial.println("Receiver: No pulse received");
  }

  delay(500); // Wait for half a second before the next measurement
}