Which way is North?

This is a great article by K&J Magnetics, who supply the magnet spheres I use in the Styli:

https://www.kjmagnetics.com/blog/which-pole-is-north

If you ever wondered how polarity is determined, this will provide some background.

The Core Matrix board in the Core64 kit uses hall sensors, which are capable of measuring the magnetic field polarity and strength. In my application, I ignored the polarity and just use the absolute value of the strength to trigger the “buttons.”