The Humidity (and Temperature) Sensor is a board that carries an SHT21 digital humidity and temperature sensor from Sensirion.

It has 4 pins that can mount directly on the Arduino’s analog pins. Two of the four pins are Ground and +5V; the other two are

clock and data pins making up the 2-wire serial interface.

It transmits data to the Arduino over an I2C protocol, and comes with built-in 5V tolerance to be powered directly from the

analog pins.

The Antipasto Arduino IDE has an integrated library that makes the humidity sensor plug-and-play.