Raspberry Pi Enable I2C

On the Pi, I2C is disabled by default. The first thing to do, is run the commandsudo nano /etc/modprobe.d/raspi-blacklist.conf . In this file, there is a comment, and two lines. Add a hash before the I2C line, to comment it out.
Original:# blacklist spi and i2c by default (many users don’t need them)blacklist spi-bcm2708
blacklist i2c-bcm2708

Convert to this:

# blacklist spi and i2c by default (many users don’t need them)

blacklist spi-bcm2708
#blacklist i2c-bcm2708

 

SOURCE