A phone on a pole is capturing the soundtrack of a street corner in San Francisco

A San Francisco man has a new spin on surveillance technology. He uses a solar-powered android phone running the song identifier app Shazam to listen and record the music passersby are listening to.

Transcript

ARI SHAPIRO, HOST:

Now a story about the sounds of city life - specifically, the music on one street corner in San Francisco's Mission District. NPR's Chloe Veltman listens in.

CHLOE VELTMAN, BYLINE: No matter the time of day, San Francisco's Mission District is busy on the ears, what with the traffic...

(SOUNDBITE OF HORN HONKING)

VELTMAN: ...The street corner banter...

UNIDENTIFIED PERSON: Hola.

VELTMAN: ...And a whole lot of music.

(SOUNDBITE OF MUSIC)

VELTMAN: NPR's microphone isn't the only device picking up tracks like these today. An innocuous-looking plastic box attached near the top of a light pole right there is also listening in.

RILEY WALZ: This is Bop Spotter. It's like a living time capsule in real time of what songs are playing.

VELTMAN: Riley Walz is Bop Spotter's creator. The 22-year-old software engineer spends his spare time dreaming up oddball projects, like a fake restaurant that mostly existed only on the internet. Walz says inside that plastic box is an old phone he programmed to do only one job.

WALZ: To record audio and then pass it to Shazam all the time.

VELTMAN: A solar panel on top of the box provides power. A microphone on the bottom captures songs and logs them on the Bop Spotter website - about 150 a day since the project launched - by artists such as Nipsey Hussle...

(SOUNDBITE OF SONG, "THAT'S HOW I KNEW")

NIPSEY HUSSLE: (Rapping) That's how I knew. That's how I knew.

VELTMAN: ...The Temptations...

(SOUNDBITE OF SONG, "AIN'T TOO PROUD TO BEG")

THE TEMPTATIONS: (Singing) Ain't too proud to beg.

VELTMAN: ...And Yahir Saldivar.

(SOUNDBITE OF SONG, "LA CUMBIA DEL CASTOR")

YAHIR SALDIVAR: (Singing in Spanish).

VELTMAN: Nate Sloan is a musicologist and the co-host of the "Switched On Pop" podcast.

NATE SLOAN: One of the things that really defines the urban soundscape to me is all the music that you hear coming out of car stereos, people's phones, from retail stores and coffee shops.

VELTMAN: Sloan says these songs are frustratingly ephemeral. The car drives off, or you walk past the store. That's where Bop Spotter comes in.

SLOAN: This kind of captures those sounds and records them in a way that makes it this really wonderful archive of a specific intersection.

VELTMAN: Sarah Koellner researches culture and surveillance. She says Bop Spotter is fun, but it also raises serious questions about contemporary surveillance culture.

SARAH KOELLNER: Do we enjoy the entertainment, or is it something that we're actually appalled by, that someone is, like, listening in, right?

VELTMAN: Riley Walz says he named Bop Spotter after ShotSpotter, a surveillance technology police departments use to track the location of gunshots, but he's not making a political point.

WALZ: This is culture surveillance, where I'm picking up on people's activities down here, but it's just music.

VELTMAN: The project is resonating. Walz says people in places like New York and Berlin have gotten in touch about creating their own Bop Spotters.

WALZ: Get a network of these going, and kind of compare city to city.

VELTMAN: He says he's also been joking about creating a Bop Spotter that captures people's sneezes and then yells, bless you, in response.

Chloe Veltman, NPR News.

(SOUNDBITE OF LOLA YOUNG SONG, "CONCEITED") Transcript provided by NPR, Copyright NPR.