I have a sensor tag from Texas and have been able to communicate with it over BLE and get magnetometer readings using a node.js library.
However I am tough time going from the x,y,z mag. axis readings to being able to say NORTH, SOUTH, EAST, WEST. Any pointers in the direction would be of great help.
Thanks. :)
Determine which axis of the device is going to point North. That is your north unit vector. Convert the x, y, and z magnetometer data to a vector. From there, use the dot product. \$cos\theta=\dfrac{A\cdot B}{|A||B|}\$
After you have that angle, there are 4 quadrants to a compass:
Set up a set of conditional statements for those ranges.
