As a baby, Ari Weinstein was mesmerized by light switches. By 2, he had mastered the family TV, stereo, and VCR and soon was taking apart mechanical toys. At 6, he disassembled an old computer, reassembled it, and rejoiced when it still worked.

Now 15, the Mount Airy youth is the toast of the Internet. More than 1,100 followers track his techno exploits via Twitter.

Ari's latest feat - an online collaboration with six other inventive teenagers who have never met face to face - is the creation of software enabling Apple iPhone owners to download free, unauthorized applications.

More so than the others, Ari has not shrunk from the fame or the infamy of "jailbreaking." In hackerspeak, the term refers to circumventing the iPhone's restrictions in order to customize it for a multitude of other uses, from playing non-Apple games to accessing the Internet through a laptop.

The practice appeared shortly after the iPhone's introduction in June 2007. Ari and his confederates were able to jailbreak Apple's newest model, the iPhone 3GS, within two weeks of its June 19 release.

More than 250,000 people have gone to the Web site to download the programs that open their iPhones for modifications.

"It's really cool to have people using my software to do awesome things with their phones," said Ari, who is about to begin his sophomore year at Germantown Friends School.

Ari, who has consulted family friends who are lawyers, contends that providing unauthorized applications for iPhones is legal under the Digital Millennium Copyright Act.

"My theory is that, basically, since I paid a lot of money for this device, I should be able to put any application on it," he said.

Apple takes a dim view of his argument.

The company, which last week reported third-quarter revenue of $8.34 billion, sells its own iPhone applications through its online App Store. It has filed documents with the U.S. Copyright Office challenging the legality of unauthorized iPhone applications.

"The vast majority of customers do not jailbreak their iPhones, and for good reason," an Apple spokeswoman said Thursday. "These hacks not only violate the warranty, they will also cause the iPhone to become unstable and not work reliably."

A ruling by the copyright office is expected in the fall.

And if it favors Apple?

Simple, Ari said: "I will have to stop doing it."

He would not succumb to boredom.

He blogs under the name AriX at, and has created Web sites and launched business ventures.

"I love seeing how things work," he said, "and I always have."

His parents, Ken and Judy Weinstein, have been juggling requests for local and national media interviews since the Wall Street Journal reported on the teens' software earlier this month.

They are not surprised that their son is a cybersensation. Ken Weinstein, a Mount Airy developer, recalls his late father, Norman, holding baby Ari for hours to flip light switches.

"Now it becomes apparent," Weinstein said. "It wasn't about the lights but trying to figure out how they worked."

Matt Zipin, a veteran technology teacher at Germantown Friends, is wowed by the teen's skills. When it comes to iPhones, he said, Ari is singular.

"I have seen kids who are really good - kids who are now at Microsoft and Cisco," Zipin said. "Ari is unusual in that his skill set is fairly narrow but really deep."

A kindred spirit

Ari got an iPod mini when he was 11 but thought he should be able to play more games than the four that Apple had installed. So he taught himself some programming to add extras.

In 2007, he was given an iPod touch - essentially an iPhone minus the phone - as a bar mitzvah present. Not content with the applications, he started tinkering.

"Once I got interested in iPods, it was not that big of a jump to go to iPhone hacking," Ari said. "It was natural for me to say I want this to do more than Apple has it do."

About the same time, he found someone who shared his techno passions.

At Germantown Friends, seventh-grade classmates had been telling Ari about a kid named Ben.

At Abington Friends, seventh-grade classmates of Ben Feldman's had been telling him about a kid named Ari.

They met at a bar mitzvah in April 2007 and were soon business partners.

"It was so unbelievable for both of us to be able to start mentioning things we both knew about but nobody else did," Ben, also 15, of Northeast Philadelphia, said.

Since age 3, he had been spending most of his free time on computers. "Ben is the kid who does not read novels," said his mother, Paula Weiss, a lawyer and Philadelphia deputy finance director. "He reads computer-programming books; he reads for information. He and Ari are kindred spirits."

Ben was not involved in the latest iPhone venture. But he and Ari had teamed up for a previous enterprise - software that opened earlier iPhone models and the iPod Touch. It was released online at on Oct. 14, 2007, and downloaded more than 1 million times; grateful users donated a few thousand dollars.

Ben "wrote a really good press release and sent it out to bunch of news sites on the Internet, and it just spread," Ari said. "I was really famous for a few days."

They used some of the contributions to start a business providing backup servers for Web sites. It folded quickly.

Corporations, Ari said, "would not trust a small business, especially one run by kids."

Their latest project is DeskConnect, a subscription service that will allow users to easily access home-computer files and whatever is displayed on the screen from laptops, phones, and other electronic devices through a Web site. Ben and Ari expect the Mac version, at least, to be ready for launch shortly after school starts in the fall.

"We always have new ideas," Ben said. "We're always figuring out new things we would use ourselves."

He and Ari know college is in their futures, but they haven't focused on it.

"I want to go into something computer-related when I'm older," Ari said. "But I don't know what yet. I'd love to own a business."

So would Ben.

"Every next thing we do is iteratively better and better. . . . Everything is of a higher and higher quality with better business plans," Ben said. "My goal really is to be able to live off one of the things that Ari and I do."