#include <OneWire.h>
#include <DallasTemperature.h>
#define ONE_WIRE_BUS 2    //DS18B20 - DQ pin connect to Arduino
#define LED_PIN 13        //LED pin connect to Arduino

OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

void setup() {
    Serial.begin(9600); 
    sensors.begin();     
    pinMode(LED_PIN, OUTPUT);   //Set LED pin as o/p
}

void loop() {
    sensors.requestTemperatures(); //Request temperature from sensor
    float temperature = sensors.getTempCByIndex(0); //Get temp in Celsius
    Serial.print("Temperature: ");
    Serial.print(temperature);
    Serial.println(" °C");

    //LED - ON if temperature>25°C
    if (temperature > 25.0) {
        digitalWrite(LED_PIN, HIGH); //LED on
    } else {
        digitalWrite(LED_PIN, LOW);  //LED off
    }
    delay(1000); //Wait 1s before next reading
}