I2C

I2C is standard for communicating with microcontrollers. It stands for Inter-Integrated Circuit. It allows for many devices to communicate using only four wires, +5V, GND, SDA, and SCL. Club hardware that uses this standard include the SRF10 ultrasonic rangefinder and the CMPS03 digital compass. When using I2C hardware with the Arduino Duemillanove, SCL should be connected to A5 and SDA to A4, and each should also be connected to +5V via 4k7 to 1k8 resistors. Sketches interfacing with I2C devices will need to include the Wire.h library. For additional information, see the Arduino reference page.