have a Suunto surveyor's compass that I've carried in the map pocket on a rando bag before (many times), but never really paid it any mind.
I found a really small handlebar 1/4-20 camera mount and put that compass on my upright handlebars.
I love it there and am constantly comparing change in path direction to the wind direction, etc.
Figured out why our E-W bike expressway always feels like it has a headwind in both directions.