This comes from a footnote in the April issue of QST (Page 32):
A technical journal named The WCF Experimenter.
Its Spring, 2016, issue has some interesting projects for both the advanced builder and those with more moderate skills.
One of the latter articles describes an Arduino-based device for measuring the speed of sound at your location, by bouncing sound off a wall and measuring it's return time.
It might be a good anesthetic for cabin fever.