#include <Arduino.h>

const int trigPin = 5; // GPIO pin for the Trig of HC-SR04
const int echoPin = 18; // GPIO pin for the Echo of HC-SR04
const int ledPin = 2;   // GPIO pin for the LED

void setup() {
  Serial.begin(115200); // Start serial communication at 115200 baud rate

  pinMode(trigPin, OUTPUT); // Set the trigPin as an OUTPUT
  pinMode(echoPin, INPUT);  // Set the echoPin as an INPUT
  pinMode(ledPin, OUTPUT);  // Set the ledPin as an OUTPUT

  digitalWrite(trigPin, LOW); // Initialize trigPin to LOW
  delay(500); // Wait for 500 milliseconds to ensure the sensor is ready
}

void loop() {
  long duration, distance;

  // Trigger the sensor by sending a 10 microsecond pulse to the trigPin
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

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

  // Calculate the distance in cm
  distance = duration * 0.0344 / 2;

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

  // Control the LED based on the distance
  if (distance < 10) { // If distance is less than 10 cm
    digitalWrite(ledPin, HIGH); // Turn on the LED
  } else {
    digitalWrite(ledPin, LOW); // Turn off the LED
  }

  delay(500); // Wait for 500 milliseconds before the next measurement
}