This is a breakout board for Honeywell s HMC5843, a 3-axis digital compass. Communication with the HMC5843 is simple and all done through an I2C interface. There is no on-board regulator, so a regulated voltage of 2.5-3.3VDC should be supplied. The breakout board includes the HMC5843 sensor and all filtering capacitors as shown. The power and 2-wire interface pins are all broken out to a 0.1″ pitch header.