The SHT11 from Sensirion (Zurich, Switzerland) is a combination humidity/temperature sensor and transmits a fully calibrated digital signal to measure rh (+3.5% rh, +2% on request) and temperature (+0.5 degrees C at 20 degrees C). The unit can be directly connected to a microcontroller using a digital two-wire interface, and it features a short response time of 4 sec and a temperature range of -40 degrees to 120 degrees C.