The RHT03 (also known by DHT-22) is a low cost humidity and temperature sensor with a single wire digital interface. The sensor is calibrated and doesn't require extra components so you can get right to measuring relative humidity and temperature. Features: 3.3-6V Input 1-1.5mA measuring current 40-50 uA standby current Humidity from 0-100% RH -40 - 80 degrees C temperature range +-2% RH accuracy +-0.5 degrees C Datasheet: http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Sensors/Weather/RHT03.pdf