Examples are disclosed relating to computing devices and methods for determining angular orientations of a first planar substrate rotatably coupled to a second planar substrate. In one example, a method comprises: receiving at a three-axis magnetic sensor in the second substrate a magnetic field emanating from a magnet array in the first substrate; determining magnetic flux densities at first and second sensing axes of the sensor throughout a range of degrees; and using the magnetic flux densities to determine multiple angular orientations of the first substrate relative to the second planar substrate.