This CMPS03 is Discontinued Now, We recommend other Magnetic Sensors as a suitable replacement.
The Devantech Magnetic Compass Module CMPS03 identifies the angle of rotation in relation to the Earth's magnetic field. 0.1 degree of resolution and 3 to 4 degrees of accuracy. Can easily be connected to microcontrollers such as the BasicX or BasicATOM. Built by Devantech, this module allows you to know the orientation of your robot in relation to the North according to the calibration you did. This compass module has been specifically designed for use in robots as an aid to navigation. Indeed, robots possess multiple tools to know the distance covered, such as the "Dead Reckoning"; however, few tools are available to know the orientation of your robot. The magnetic compass is a module totally appropriate to complete the navigation system of your robot.
Accuracy:3-4 degrees approximately after calibration
Output 1Timing Pulse (1ms to 37ms in 0.1ms increments)