Quick Overview 

1. 3-axis magnetic electronic compass.
2. Precise heading information.
3. Operating Voltage: 3 -5 V DC.
4. Driver Chip: QMC5883L.
5. Communication: I2C protocol.
6. Measuring range: ± 1.3-8 Gauss.

Product Description

        The GY-271 is supposed to have an HMC5883L, but some boards have a QMC5883L which has the same basic capability, but is not compatible with the H. The GY-271 QMC5883L 3-axis Electronic Compass Module Magnetic Field Sensor is designed for low field magnetic sensing with a digital interface and it is perfect to give precise heading information. 

       If you get a GY-271 board and observe an I2C address of 0x0C and read back nothing but zeros from the board, then you probably have a QMC5883L chip! Try this library and see if it works for you. To install this library into your Arduino environment, download the latest release file to your desktop