#include <Stepper.h>
#include <DHT.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>


#define STEPS_PER_REV 200  
Stepper stepper(STEPS_PER_REV, 8, 9, 10, 11);


#define DHTPIN 7
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);


LiquidCrystal_I2C lcd(0x27,16,2);

void setup() {
  lcd.init();
  lcd.backlight();
  dht.begin();

  lcd.print("Temp Fan System");
  delay(2000);
  lcd.clear();
}

void loop() {
  float temp = dht.readTemperature(); 
  int rpm;

  
  if(temp < 25) rpm = 0;
  else if(temp >= 25 && temp < 30) rpm = 30;
  else if(temp >= 30 && temp < 35) rpm = 60;
  else rpm = 100;

  
  lcd.setCursor(0,0);
  lcd.print("Temp: ");
  lcd.print(temp,1);  
  lcd.print(" C  ");  

 
  lcd.setCursor(0,1);
  lcd.print("Fan RPM:      "); 
  lcd.setCursor(9,1);
  lcd.print(rpm);

 
  if(rpm > 0){
    stepper.setSpeed(rpm);              
    stepper.step(STEPS_PER_REV / 50);   
  }

  delay(200);  
}