[Cryptonomicon]
I've just started working on this project inspired by a passage in the novel 'Cryptonomicon' by Neil Stephenson. Something to do with contact micropohnes and vibrations of bedrocks...

Photo: contact microphone and pre-amplifier
schematic for contact microphone pre-amp
schematic for contact microphone pre-amp
...He can hear the footfalls of skerries going through the detachment's rations. He can hear the impact of waves on the shore, miles away, and the thump of the Taxi's bald tires on chuckholes out on the Road. Sounds like Taxi has a little alignment problem! He can hear the scrub, scrub of Margaret cleaning the floor in the kitchen, and some minor arrhythmias in the heartbeats of the enlisted men, and the boom of glaciers calving on the coast of Iceland, and the squarely drone of hastily machined propellers on approaching convoy ships. Lawrence Pritchard Waterhouse is plugged into the Universe in a way that exceeds even what Bletchley Park has to offer.