The LM35 is a high precision temperature sensor. It has a analog output, which is linearly proportional to the surrounding temperature. Just hook it up to a ADC pin on your microcontroller to get temperature readings.
Output calibrated in ° Celsius
0.5° C accuracy at 25° C.
Wide range of operation between -55° to +150°C
Wide range of operatin voltage ranging between 4 to 30 volts