This great little compass was designed by Robot Electronics specifically for use in robots to aid navigation. The compass uses the Philips KMZ51 magnetic field sensor, which is sensitive enough to detect the Earth's magentic field. Two of them mounted at right angles to each other can be used to compute the direction of the horizontal component of the Earth's magnetic field.
Voltage 5v
Current 20mA Typ.
Resolution 0.1 Degree Accuracy 3-4 Degrees approx (after calibration) Output 1 Timing Pulse 1mS to 37mS in 0.1mS increments Output 2 I2C Interface, 0-255 and 0-3599 SCL Speed up to 1MHz Weight 0.03 oz. Size 32mm x 35mm