A retinal scanner emitting a blue glow monitors the entrance to Andy Rubin’s home in the foothills overlooking Silicon Valley. If the scanner recognizes you, the door unlocks automatically. (The system makes it easier to deal with former girlfriends, Mr. Rubin likes to joke. No messy scenes retrieving keys — it’s just a simple database update.)
Those forced to use the doorbell are greeted with another technological marvel: a robotic arm inside the glass foyer grips a mallet and then strikes a large gong. Although Mr. Rubin won’t reveal its cost, it may be one of the world’s most expensive doorbells.
“It’s not about the cost,” said Zarko Draganic, a former colleague of Mr. Rubin’s at Apple Inc. “It’s the classic Rubin thing: You do it for the sake of doing it and because it’s cool, and as a result there’s a childlike innocence about it.”
Mr. Rubin is one of the primary architects behind another product that also smacks of potential