<ahref='as5013-test'>as5013-test/</a> contains pcb source files for a board to evaluate 3d tracking using the AS5013 (nominally an 8-bit 2-axis device). This IC contains an array of 5 hall effect elements for measuring $B_z$, sampled to 12-bits internally with these raw values available over I2C.
To characterize the use of the AS5013 as a three-dimensional tracking device, we use a 5 axis stage (2 axes motorized, 3 manual) built around two Thorlabs PT1M micrometer stages. After setting a magnet height and orientation, we can sample the 5 hall elements over a two dimensional array of magnet displacements. Executing this for a handful of magnet heights should let us fit functions for X, Y, and Z in terms of the 5 hall readings.