“Somewhere in the Mission district of San Francisco is a microphone, pointed down at the street below.”
Riley Walz hung a microphone over a San Francisco street and runs Shazam on it around the clock. It is ShotSpotter for songs, and it logs what passersby play with timestamps and a CSV export. “No one notices, no one consents,” the page says. The police version runs on the same deal, and by the page’s own account it is not very accurate.