/* DHT-22 sensor with I2C 16x2 LCD with Arduino Uno
   Temperature and humidity sensor displayed on LCD
   based on: http://www.ardumotive.com/how-to-use-dht-22-sensor-en.html and
            https://www.ardumotive.com/i2clcden.html for the I2C LCD library by Michalis Vasilakis
   Recompiled by adhitadhitadhit
   Notes: Use the LCD I2C Library from the link above. I'm not sure why, but the new LiquidCrystal library from Francisco Malpartida isn't working for me.
          Another thing, check your connections. */

// Libraries
#include <dht.h> // Sensor library using lib from https://www.ardumotive.com/how-to-use-dht-22-sensor-en.html
#include <LiquidCrystal_I2C.h> // LCD library from https://www.ardumotive.com/i2clcden.html for the I2C LCD library 
#include <ModbusRTUSlave.h>
#include <SoftwareSerial.h>

dht DHT;

// Constants
#define DHT22_PIN 2
#define SLAVE_ID 1
#define TEMPERATURE_REGISTER 0
#define HUMIDITY_REGISTER 1
LiquidCrystal_I2C lcd(0x27, 16, 2);

const byte dePin      = 4;
const byte rxPin      = 1;
const byte txPin      = 0;
// const byte buzzerPin  = 7;

SoftwareSerial mySerial(rxPin, txPin);
ModbusRTUSlave modbus(mySerial, dePin); // Use default baud rate
uint16_t holdingRegisters[2];

// Variables
float humidity;
float temperature;

void setup() {
    Serial.begin(9600);
    lcd.init();
    lcd.backlight(); // Initialize LCD and turn on backlight
    modbus.configureHoldingRegisters(holdingRegisters, 2);
    modbus.begin(SLAVE_ID, 9600);
    pinMode(8, OUTPUT); // Pin for controlling humidity conditions
    pinMode(7, OUTPUT); // Pin for controlling humidity conditions
    // pinMode(buzzerPin, OUTPUT);
}

void loop() {
    modbus.poll();
    int chk     = DHT.read22(DHT22_PIN);
    humidity    = DHT.humidity;
    temperature = DHT.temperature;

    Serial.println(humidity);
    Serial.println(temperature);

    // Print temp and humidity values to LCD
    lcd.clear(); // Clear LCD before printing new values
    lcd.setCursor(0, 0);
    lcd.print("Humidity: ");
    lcd.print(humidity);
    lcd.print("%");
    lcd.setCursor(0, 1);
    lcd.print("Temp: "); 
    lcd.print(temperature);
    lcd.print(" C");

    if (humidity > 50) {
        // tone(buzzerPin, 100, 1000);
        digitalWrite(8, HIGH); // Control humidity conditions based on threshold
        digitalWrite(7, LOW);
    } else if (humidity < 30) {
        digitalWrite(8, LOW); // Control humidity conditions based on threshold
        digitalWrite(7, HIGH);
    }

    // Store values in Modbus registers (correct way)
    holdingRegisters[TEMPERATURE_REGISTER]  = static_cast<uint16_t>(temperature * 10);
    holdingRegisters[HUMIDITY_REGISTER]     = static_cast<uint16_t>(humidity);

    delay(2000);
}