DS18B20

#include <OneWire.h>
#include <DallasTemperature.h>

#define ONE_WIRE_BUS 2

OneWire oneWire(ONE_WIRE_BUS);

DallasTemperature sensors(&oneWire);

void setup() {
  sensors.begin();
  Serial.begin(9600);
}

void loop() {
  sensors.requestTemperatures();

  Serial.println(sensors.getTempCByIndex(0));
  delay(500);
}