If you want to know what’s going on with the ground, geologically speaking, a geophone is a great tool to have. It lets you listen in on the rumbles and grumbles beneath your feet, and can give you great insight into matters of seismic importance. [mircemk] has designed a very capable geophone that’s simple enough for you to build at home.
This is a companion discussion topic for the original entry at https://hackaday.com/2024/03/02/diy-geophone-build-performs-well/