The HMC5883L 3-Axis Compass Module is a low cost magnetometer with an I2C interface.
This compass allows a robot to determine its bearing relative to the Earth's magnetic north. It works a lot like the familiar compass that has a needle that always points north, but to read it your microcontroller must talk to it using I2C.
This module features extra circuitry to allow it to operate with both 3.3V and 5V microcontrollers. It comes with optional straight and right angle male header pins that can be soldered into place.
|1||VCC||Voltage input 3-5V|
|5||DRDY||Data ready (optional)|