#include "dht.h"
#define MAX_TEMP 45 // Define the maximum temperature threshold
#define MAX_HUMIDITY 70 // Define the maximum humidity threshold

#define dht_apin A1 // Analog Pin sensor is connected to

float temp, humidity;

dht DHT;

#define fan 9
#define alarmPin 10 // Define the pin for the alarm sensor

void setup() {
  Serial.begin(9600); //this is for the serial monitor
  delay(500); //Delay to let system boot
  Serial.println("DHT22 Humidity & temperature Sensor \n\n");
  pinMode(fan, OUTPUT); // Giving Fan Current.Making Fan Pin 9 For Output
  pinMode(alarmPin, INPUT_PULLUP); // Set the alarm pin as input with internal pull-up resistor
}

void loop() {
  DHT.read22(dht_apin);

  Serial.print("Current humidity - ");
  Serial.print(DHT.humidity);
  Serial.print("% ");
  Serial.print("temperature = ");
  Serial.print(DHT.temperature);
  Serial.println("C");

  temp = DHT.temperature;
  humidity = DHT.humidity;

  // Calculate fan speed
  float fan_speed = 0.00593975 * temp + 1.25319841 * humidity + 29.137272695176353;
  fan_speed = (fan_speed / 100) * 255;
  int speed = (int)fan_speed;
  float per = (speed * 1.0 / 255) * 100;

  Serial.print("fan speed ");
  Serial.print(per);
  // Serial.println("%");

  // Control fan speed
  analogWrite(fan, speed);

  // Check if conditions for sounding the alarm are met
  if (temp > MAX_TEMP || humidity > MAX_HUMIDITY || digitalRead(alarmPin) == LOW) {
    // Activate alarm
    Serial.println("ALARM! Temperature/humidity out of range or alarm sensor triggered!");
  }

  delay(5000); //wait for 5 seconds before accessing sensor again
}