/*
--------------------------------------------------
Project : Ultrasonic Distance Meter with I2C LCD
Designed & Explained by : Shubham Sutar
YouTube Channel : Technical Shubham

Description:
This project measures distance using an ultrasonic sensor
and displays the value in both centimeters and inches
on a 20x4 I2C LCD display.
--------------------------------------------------
*/

// Include I2C LCD library
#include <LiquidCrystal_I2C.h>

// LCD address 0x27, 20 columns, 4 rows
LiquidCrystal_I2C lcd(0x27, 20, 4);

// Ultrasonic sensor pins
#define TRIG_PIN 3
#define ECHO_PIN 2

// Variables to store distance
float distanceCM;
float distanceInch;

// Function to read ultrasonic sensor distance (in microseconds)
long readUltrasonicDistance()
{
  // Send trigger pulse
  pinMode(TRIG_PIN, OUTPUT);
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);

  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // Read echo pulse
  pinMode(ECHO_PIN, INPUT);
  return pulseIn(ECHO_PIN, HIGH);
}

void setup()
{
  Serial.begin(9600);

  // Initialize LCD
  lcd.init();
  lcd.backlight();

  // Welcome message
  lcd.setCursor(2, 1);
  lcd.print("Distance Meter");
  lcd.setCursor(3, 2);
  lcd.print("Technical Shubham");
  delay(3000);
  lcd.clear();
}

void loop()
{
  // Convert time to distance (Speed of sound = 0.0344 cm/us)
  distanceCM = (0.0344 / 2) * readUltrasonicDistance();
  distanceInch = distanceCM / 2.54;

  // Serial Monitor output (optional for debugging)
  Serial.print("Distance: ");
  Serial.print(distanceCM, 1);
  Serial.print(" cm | ");
  Serial.print(distanceInch, 1);
  Serial.println(" inch");

  // Display labels
  lcd.setCursor(0, 0);
  lcd.print("Inches");

  lcd.setCursor(13, 0);
  lcd.print("CM");

  // Display values
  lcd.setCursor(0, 1);
  lcd.print(distanceInch, 1);

  lcd.setCursor(12, 1);
  lcd.print(distanceCM, 1);

  delay(2000);
  lcd.clear();
}