The HMC5883L is a triple-axis magnetometer compass, which uses I2C for communication.

Compass heading accuracy of 1° to 2°, provided by internal 12-bit ADC (Analog-to-Digital Converter).

Includes on-board voltage regulator, allowing you to power the module with voltages between 3.3V and 6V.

The module includes on-board pull-up resistors on the I2C lines.

There is a data ready pin (pin DRDY) you can use to make your communication with the module more efficient; refer to the datasheet below for details.

Since this module has such great compass heading accuracy, it is great for giving your robot precise navigation abilities.