#include <LiquidCrystal_I2C.h>
#include <SD.h>

LiquidCrystal_I2C lcd(0x27, 20, 4);
const int trg = 4;
const int eco = 3;
const int button = 5; // Add a button pin

void setup() {
  lcd.init();
  lcd.backlight();
  lcd.setCursor(1, 0);
  pinMode(trg, OUTPUT);
  pinMode(eco, INPUT);
  pinMode(button, INPUT); // set button as input

  // Initialize SD card
  if (!SD.begin(4)) {
    lcd.println("SD card initialization failed!");
    delay(1000);
    return;
  }
  lcd.println("SD card initialized.");
  delay(1000);
}

void loop() {
  digitalWrite(trg, HIGH);
  delay(10);
  digitalWrite(trg, LOW);

  long duration = pulseIn(eco, HIGH);
  long distance = duration / 58.2;

  // Display distance on LCD
  lcd.setCursor(0, 0);
  lcd.println("Dist:");
  lcd.setCursor(7, 0);
  lcd.println(distance);
  lcd.setCursor(14, 0);
  lcd.println("cm");
  float distanceInches = distance / 2.54;
  lcd.setCursor(0, 1);
  lcd.println("Dist:");
  lcd.setCursor(7, 1);
  lcd.println(distanceInches);
  lcd.setCursor(14, 1);
  lcd.println("in");

  // Check if button is pressed
  if (digitalRead(button) == HIGH) {
    // Create a file on the SD card
    File dataFile = SD.open("distance.txt", FILE_WRITE);

    // Write the distance to the file
    dataFile.print("Distance: ");
    dataFile.print(distance);
    dataFile.println(" cm");

    // Close the file
    dataFile.close();
    lcd.setCursor(0, 0);
    lcd.println("Distance saved!");
    delay(1000);
  }
  delay(16);
}