#define TRIG_PIN 9
#define ECHO_PIN 8
#define LED_PIN 7
#include <LiquidCrystal_I2C.h>
#include <Wire.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);
  Serial.begin(9600); // Initialize serial communication at 9600 baud
  lcd.init();
  //lcd.begin(16,2);
  lcd.backlight();
  lcd.clear();
}

void loop() {
  // Send a 10 microsecond pulse to the trigger pin
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // Measure the duration of the echo pulse
  long duration = pulseIn(ECHO_PIN, HIGH);

  // Calculate the distance in centimeters
  float distance = (duration / 2.0) / 29.1;

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

  // Control the LED based on the distance
  if (distance <= 40) {
    digitalWrite(LED_PIN, HIGH); // Turn on the LED if the object is within the threshold distance
    delayMicroseconds(100);
    digitalWrite(LED_PIN, LOW);
    delayMicroseconds(100);
    lcd.setCursor(0, 0);
    lcd.print("RobotX Siemreap");
    lcd.setCursor(0, 1);
    lcd.print("Thank You!");
    delay(100);
  } else {
    digitalWrite(LED_PIN, LOW); // Turn off the LED if the object is beyond the threshold distance
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Hello");
  }
  // Wait a bit before the next measurement
  delay(500);
}