This is a 3-Axis Compass using the low-cost but three-axis HMC5883 from Honeywell, allowing us to offer our module at a very nice price point compared with other electronic compass options. The chip is a 3.3V chip but we've included a regulator and level shifting for the I2C signals so the module will work with microcontrollers running at any voltage between 3 and 6 volts - perfect for Arduinos, BBBs and JeeNodes. We've even included a JeeNode header port for users who wish to use the board with their JeeNodes. There is a JeeNode example posted below, as well as Arduino code.

The z-axis is not addressed in the code yet, but we hope to make a combination compass and accelerometer board that achieves a true tilt-free compass. Until then, this is a great option with much less sensitivity to tilt than dual axis compasses. 

Applications

• Navigation
• Robot navigation
• Home brew virtual reality systems
• Interactive installations
• Astronomy
• IMU (inertial measurement unit) with an accelerometer for tilt-correction
  

Pin References

• G - Ground
• +V - 5V input or any voltage between 3 & 6 volts
• SDA - Serial Data
• SCL - Serial Clock
  

Specifications

• 1°-2° accuracy
• I²C output
• 5V regulator onboard
• JeeNode Ports-compatible pinout
  

Resources

• HMC5883 Datasheet
• Modern Device Compass Sensor Eagle Files  
• Schematic in pdf (bitmap) form
  
• STM paper on tilt-compensation
• Honeywell application note 1
• Honeywell application note 2
  
• Arduino Code for the HMC5883 (thanks to Seeed Studio)
• Using the HMC5883 with JeeNodes