Neat. If you want to make it more practically useful you will need to include some kind of magnetic compensation map. That's one of the reason navigation apps usually are a bit larger, they require a lot of data to function well world wide. Best of luck with this, it looks very promising!

Thanks! Currently, MBCompass can show both magnetic north using Android’s sensor fusion and true north (based on WGS84 geodetic coordinates).

Adding a magnetic compensation map sounds like a great fit for improving global accuracy without changing the app’s core goals. Thanks for the suggestion.