Interesting article about Arduino and I2c
Artigo Interessante sobre o bus I2c e ARDUINO.
The i2c bus ( i square c ) uses only two wires, saving a lot of connections and circuitry. One deviece is the bus master and request all information from others devices connected.
Used on Pc boards and home devices. Arduino has support and specilized libraries for this bus.
This is the link: I2c Arduino