#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <HX711.h>
#include <SD.h>
#include <EEPROM.h>

const int DOUT_PIN = 9; // Connect HX711 DOUT pin to Arduino digital pin 9
const int CLK_PIN = 8;  // Connect HX711 CLK pin to Arduino digital pin 8
const int SD_CS_PIN = 10; // Connect SD card CS pin to Arduino digital pin 7

HX711 scale;

LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27, 16 columns and 2 rows

unsigned long previousSerialMillis = 0;
unsigned long previousSDMillis = 0;
const long intervalSerial = 2000; // 2 seconds interval for serial output
const long intervalSD = 5000;     // 5 seconds interval for SD card logging

// Scale factor for calibration
const float SCALE_FACTOR = 0.42;

void setup() {
  Serial.begin(9600);
  lcd.begin(16, 2);

  scale.begin(DOUT_PIN, CLK_PIN);

  // Apply the scale factor
  scale.set_scale(SCALE_FACTOR);

  if (!scale.is_ready()) {
    Serial.println("Error initializing the HX711. Check your connections.");
    while (1);
  }

  if (!SD.begin(SD_CS_PIN)) {
    Serial.println("Error initializing SD card. Check if the card is inserted properly.");
    while (1);
  }

  lcd.print("Weight Logger");
  delay(2000);
  lcd.clear();
}

void loop() {
  unsigned long currentMillis = millis();

  // Display current weight on LCD
  float weight = scale.get_units(10);
  lcd.setCursor(0, 0);
  lcd.print("Weight: " + String(weight, 2) + " g");

  // Log data to SD card every 5 seconds
  if (currentMillis - previousSDMillis >= intervalSD) {
    previousSDMillis = currentMillis;

    File dataFile = SD.open("datalog.txt", FILE_WRITE);

    if (dataFile) {
      dataFile.println("Weight: " + String(weight, 2) + " g");
      dataFile.close();

      Serial.println("Data logged to SD card.");
      lcd.setCursor(0, 1);
      lcd.print("Logged to SD");
      delay(1000); // Display the message on LCD for 1 second
      lcd.clear();
    } else {
      Serial.println("Error opening datalog.txt");
      lcd.setCursor(0, 1);
      lcd.print("SD Card Error");
      delay(1000); // Display the message on LCD for 1 second
      lcd.clear();
    }
  }

  // Print weight to serial monitor every 2 seconds
  if (currentMillis - previousSerialMillis >= intervalSerial) {
    previousSerialMillis = currentMillis;
    Serial.println("Current Weight: " + String(weight, 2) + " g");
  }
}