This time, venture capitalists loved the idea. So did Craig McCaw, the early cellular telecommunications pioneer who is now chairman of Clearwire, a wireless network operator. As Mr. Rubin was negotiating terms with Mr. McCaw, he sent an e-mail message to Mr. Page informing him of the potential partnership. Within weeks, Google acquired Android for an undisclosed sum. Mr. McCaw declined to comment on the sale.

AS a testament to Mr. Rubin’s inner robot, a kitchen cabinet in his home bears a long scar from a laser-controlled Segway, the self-balancing, two-wheeled scooter, that crashed into it recently. It’s just one example of the web of computer technology that he lives in. Mr. Rubin has also tricked out his home theater system to slightly brighten his living-room lights once the screen credits roll at the end of a movie. Several model helicopters are parked downstairs in his house, all programmed to fly autonomously.

Mr. Rubin readily acknowledges his obsession with consumer gadgets and even more expensive toys — an obsession that put him at odds with Google’s stated aversion to conspicuous consumption.

The day before Google went public in 2004, Wayne Rosing, then the vice president for engineering, stood on a stage during a companywide meeting and brandished a baseball bat. He threatened to use it on anyone’s car in the Google parking lot that was anything flashier than a 3 Series BMW.

As a result, Mr. Rubin had to buy a new car when he came to Google. (A souped-up German sports car that he recently acquired sits at home in his garage.) He acknowledges the discomfort created by the situation. “One of the things that Google’s really good at is not encouraging conspicuous consumption,” he says. “I’m a big fan of well-engineered things, and so I’m wrestling with how those two things can coexist.”

Mr. Rubin is also wrestling with another responsibility: trying to reinvent the cellphone on his second try. He declined to offer any insights into his strategy, and whether he has the answer won’t be clear for about a year — perhaps longer. Google has a tremendous amount of corporate momentum, and its search service is a huge consumer magnet. At the same time, wireless carriers jealously guard their networks and worry constantly about the possibility of losing control to potential competitors like Google.

Moreover, the market is already crowded. Microsoft got a head-start with its Windows Mobile platform a half-decade ago and in the past year has accelerated its efforts by persuading hand-set makers like Motorola, Palm and Samsung to include the software with its phones. Microsoft is certain to invest heavily to ward off Google’s incursions into the market.