Fred Leveau and Sabri Sansoy spend much of their week programming for an advertisement firm, but this weekend they’re focusing those skills on a device that warns people with asthma and other breathing problems about adverse changes to air quality.

Leveau and Sansoy, of Marina Del Rey, teamed up at Hack for LA, a two-day challenge at Los Angeles City Hall tasking programmers, designers and app developers to use public data to create a Web or mobile application that benefits society.

“If it was not within the context of a hackathon, life would get into the way,” Leveau said of his and Sansoy’s participation.

The team’s prototype is an electronic canary — the bird used by miners to warn them of gas leaks — that pulls data from air quality monitors to convey information through the bird’s colors. The electronic bird only requires someone to glance at it to know what to expect when they get outside.

“They would have to go looking for that data, you’d have to make an effort to make sense of it or to even find it,” Leveau said. “This device is a way to visually display that information.”

The canary was one of dozens of ideas coming to fruition at Hack for LA. Organizers partnered with Venice-based startup Suprmasv to create the crowd-funded bounties of up to $3,000 to give out as prizes.

Across City Hall’s 10th floor, teams of students, hackers and technologists sprung up around conference tables crowded with laptops, water bottles and containers of caffeine.

In one room, dozens of Los Angeles Unified School District students learned the basics, while others picked up new skills from mentors. North Hollywood High School student Henry Birge-Lee’s team, which previously won a national programming contest, started work on a closed messaging system that allows teachers and students to communicate outside of school. The idea came from poor experiences using systems like Facebook to get help with homework or to get questions answered.

“We really wanted to upgrade the flow of communication between the teacher and the students,” Birge-Lee said.

Loyola Marymount students Jasmine Dahilig, Andrew Akers and Matt Coccia worked together to take data from the affordability index to help homeowners find affordable housing near like-minded people.

“We are building a Web app that will display geolocational data for affordable housing in Los Angeles,” Dahilig said.

In the room next door, Dave Gerner’s team began work on an application that helps graffiti artists find legal canvasses.

“Our idea is to match up business and residential owners with artists who want to display their artwork,” Gerner said.

The Los Angeles resident volunteered for a Hack for LA event in Boyle Heights last year, but he said the new location at City Hall made the event feel more legitimate.

The hackathon’s venue came from the strong support it got from Mayor Eric Garcetti, who wants to turn Los Angeles into a technology centric city. Garcetti has an uphill battle. The California Emerging Technology Fund ranked Los Angeles as the second to last city in California for Internet access and estimated between 14-30 percent of residents do not have access.

Hack for LA ran parallel to Garcetti’s #TechLA conference which featured panels on topics like autonomous vehicles, alternate reality games and LA’s growing tech economy. Garcetti kicked off Saturday with the relaunch of DataLA, the city’s portal for data sets on topics like housing, unemployment and public safety. City hall tasked the hackers with using the data during the challenge.

More than $3 trillion in economic value nationally comes from open data and civic hacking makes data more accessible, according to Brian Forde, a senior adviser to U.S. Chief Technology Officer Todd Park.

“Open data is not useful unless it is put to use,” Forde said. “You have companies that built billion-dollar companies on open data.”

If the country wants to stay competitive, it has to use events like Hack for LA to interest young people and minority groups in the technology field, Forde said.

“If any city is going to contribute to the diversity of the tech sector in America, it’s going to be the city of Los Angeles,” Forde said.