#include <Wire.h>
#include <DHT.h>

// DHT11 sensor setup
#define DHT_PIN 18
#define DHT_TYPE DHT11
DHT dht(DHT_PIN, DHT_TYPE);

// Ultrasonic sensor setup
#define TRIG_PIN 13
#define ECHO_PIN 12
long duration;
int distance;

// LDR sensor setup
#define LDR_PIN 34
int ldrValue;

// Gas sensor setup (MQ-2)
#define GAS_SENSOR_PIN 35
int gasValue;

void setup() {
  // Initialize serial communication
  Serial.begin(115200);

  // DHT11 sensor initialization
  dht.begin();

  // Ultrasonic sensor pins
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);

  // Setup LDR sensor (Analog input)
  pinMode(LDR_PIN, INPUT);

  // Setup Gas sensor (Analog input)
  pinMode(GAS_SENSOR_PIN, INPUT);

  Serial.println("Smart Home Monitoring System Initialized.");
}

void loop() {
  // Read data from DHT11 sensor
  float temperature = dht.readTemperature();  // Temperature in Celsius
  float humidity = dht.readHumidity();        // Humidity percentage
  
  if (isnan(temperature) || isnan(humidity)) {
    Serial.println("Failed to read from DHT sensor!");
  } else {
    Serial.print("Temperature: ");
    Serial.print(temperature);
    Serial.print(" °C, Humidity: ");
    Serial.print(humidity);
    Serial.println(" %");
  }

  // Read distance from Ultrasonic sensor
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  duration = pulseIn(ECHO_PIN, HIGH);
  distance = duration * 0.034 / 2;  // Calculate the distance in cm

  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  // Read LDR value (light level)
  ldrValue = analogRead(LDR_PIN);
  Serial.print("LDR Value (Light): ");
  Serial.println(ldrValue);

  // Read Gas sensor value
  gasValue = analogRead(GAS_SENSOR_PIN);
  Serial.print("Gas Sensor Value: ");
  Serial.println(gasValue);

  // Check for potential gas leak
  if (gasValue > 400) {  // You might need to adjust this threshold depending on the environment
    Serial.println("Warning: Gas Leak Detected!");
  }

  delay(2000); // Delay for 2 seconds before taking next reading
}