#include <LiquidCrystal.h>  // Include library for LCD display (optional)

const int tempPin = A0;    // Pin connected to LM35 sensor
const int fanPin = 9;      // Pin connected to fan (PWM pin)
const int transistorPin = 3; // Pin connected to transistor base

int tempValue;
int fanSpeed;

// Create LCD object (if using an LCD display)
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

void setup() {
  pinMode(fanPin, OUTPUT);
  pinMode(transistorPin, OUTPUT);
  Serial.begin(9600);  // Initialize serial communication (for debugging)

  // Initialize LCD (if using)
  lcd.begin(16, 2);
  lcd.print("Temp: ");
}

void loop() {
  tempValue = analogRead(tempPin);
  float temperature = tempValue * 5.0 / 1024.0 * 100;  // Convert to Celsius

  Serial.print("Temperature: ");
  Serial.print(temperature);
  Serial.println(" C");

  fanSpeed = map(temperature, 25, 40, 0, 255);  // Map temperature to fan speed
  analogWrite(fanPin, fanSpeed);

  // Display temperature on LCD (optional)
  lcd.setCursor(6, 0);
  lcd.print(temperature);
}