Thermocouples are very sensitive, requiring a good amplifier with a cold-compensation reference. The MAX31855K does everything for you and can be easily interfaced with any microcontroller, even one without an analog input.
Features:
3.3 to 5v power supply and logic level compliant
Works with any K type thermocouple
Will not work with any other kind of thermocouple other than K type
Working temperature: -20 ℃ ~ 85 ℃
Working voltage: 3.0 ~ 5.5V; working current: 50mA