The I2C (pronounced “I squared C”) interface bus is a standard for connecting microcontrollers and peripherals together. I2C is sometimes referred to as Two Wire Interface (TWI). All the Arduino boards have at least one I2C interface to which you can attach a wide range of peripherals. Some examples are shown in Figure 9-1.
Figure 9-1 A collection of I2C devices.
The three devices on the top row of Figure 9-1 are all display modules from Adafruit. On the bottom row, starting on the left, is a TEA5767 FM receiver module. You can find these modules on eBay and elsewhere for a few dollars. The TEA5767 provides you with a full FM receiver ...