Rafael Lozano-Hemmer was in town in August to prepare for his mega-public art installation Open Air, which debuts 8pm Sept. 20 on the Ben Franklin Parkway. Open Air involves big spotlights that send beams of light into the night sky, triggered by people’s voices speaking into their cellphones. He tells us how that works. We ask the Mexican-born Canadian artist about the possibility of migrating birds flying into his lights, and about how he wound up as a public artist (his degree is in engineering). “Open Air” was commissioned by the Association for Public Art (formerly the Fairmount Park Art Association), and is appearing in conjunction with the Philadelphia Fringe Festival and Design Philadelphia. Below is a short sample from our interview. The full podcast will run next week.