You haven't bought a mobile phone, music player or computer yet that uses any of the novel inventions that Chris Harrison has created.

But in 10 to 15 years a lot of people in the human computer interaction field think you will.

Mr. Harrison, 25, a third-year doctoral student in HCI at Carnegie Mellon University, has spent much of his fledgling career trying to figure out how to make mobile devices interact more directly with people -- to the point where you no longer have to push a button on your mobile phone or music player; instead, you'd use your body.

His latest foray into this futuristic world is called Skinput, a device that is just the beginning of a concept but that has already managed to generate serious buzz in the field. A YouTube video of it has been viewed by nearly 500,000 people over the last month.

And today, when he demonstrates Skinput at the CHI 2010 conference in Atlanta -- the largest annual gathering of experts in human computer interaction -- hundreds of the leaders in the field are expected to watch.

"Chris is just stellar," said Desney Tan, a senior researcher at Microsoft Research in Redmond, Wash., who oversaw Mr. Harrison's creation of Skinput during a research internship there last summer. "You can teach creativity to some degree. But some people have it in their genes, and Chris has it in his genes."

Skinput is just the latest example of that creativity.

It's his attempt to solve the basic conundrum facing the entire mobile-device world and anyone who has ever mistyped a phone number or misspelled a text message using the smaller and smaller number and letter keys we're given.

"Our computers are getting faster, have more hard drive and more options for us to use. That changes all the time," said Mr. Harrison, sitting on a stool in DevLab, a pleasantly cluttered and bright work area at CMU that is partly decorated by artwork he made out of multiple discarded computer motherboards. "The things that haven't changed are our finger size and the available surface area. We can't engineer our way out of that."

His solution?

"We need to steal surface area from the environment," he said.

He has previously worked on research that would allow a user to simply whack a cell phone still in his pocket to operate it, and Scratch Input, which allows people to scratch a table or wall a certain way to make nearby devices work.

Skinput, like the name implies, makes use of the yards of surface area we all have on our skin.

"It uses the body as the transmitting media," Mr. Harrison said.

Using a sensitive microphone placed on the body, a computer analyzes the mechanical vibrations of various taps on different parts of the body and distinguishes them from taps even less than an inch away. Each tap can be made to correspond to a different command to say, change a song, or call a certain person, or dial a number.

A small projector can also show specific directions to tap on your skin, like a number pad on the palm of your hand to dial a phone.

The aha! moment came late one night mid-summer in the Microsoft lab where he was working. After spending a month being frustrated by attempts that simply didn't work, or, like one idea that used wires along the body but was "too invasive," he said, he was in deep thought about what to try next.

"I was listening to my arm with a stethoscope and tapping it and noticed that there were slight frequency variations," he said. "Then I plugged a microphone in and noticed a systematic difference in locations, and then I put it into a computer. Over the next two to three days I feverishly coded a program and then it just worked."

It was so well received by Microsoft that he was asked to demonstrate Skinput to various product groups at the company and the device was kept under tight security until the company could quickly and carefully apply for the necessary patents to protect the rights to it.

"This is part of a much larger agenda of what is the next interactive paradigm," said Dr. Tan, who got his doctorate in computer science at Carnegie Mellon in 2004. "We've been through the mouse and keyboard interface. And I think [Skinput] is just the beginning of a long line of work in this area."

Because Skinput is so forward-thinking, 10 to 15 years would be a typical time frame for such a novel technology to become part of a consumer product. That's about the same time it took touch-screens and wireless technology to reach the marketplace.

Who knows what ideas Mr. Harrison will be working on by then, though everyone who knows his work is eager to see what it will be.

"In terms of inventiveness and proficiency he's probably the strongest student I've ever worked with," said Scott Hudson, the founder of the human computer interaction Ph.D. program at Carnegie Mellon and Mr. Harrison's adviser.

Mr. Harrison was born in England just six months before his father, Terry Harrison, an anthropology professor, took a job at New York University, where he continues to study human origins. The family moved to Manhattan and later Mount Kisco, a northern suburb of the city.

"I suppose he was always a creative child, but he wasn't much of a reader early on," said his mother, Terri, an occupational therapist. "I didn't see this creativity from the cradle, though. He was a late bloomer. It was slow and then meteoric and it's still going."

She pegs the steep learning curve to a research science class he took starting in 10th grade that put him deep into research, which Mr. Harrison decided he would do on batteries for a local company, Curtis Instruments, in Mount Kisco. He became interested and called the company himself after learning on a trip to India that Curtis made components for electronic rickshaws there.

"It was very unusual for anyone to contact us this way," said Wilfredo Chaluisant, a researcher at Curtis who became Mr. Harrison's mentor there for three years. "He was a kid out of central casting with freckles and sort of a Norman Rockwell-character about him. He threw himself into the research and spent a lot of time at our lab."

Another early mentor was Gene Brewer, a microbiologist and author of the K-PAX science fiction novels.

Mr. Brewer happened to live in the same building as the Harrisons in Manhattan and took the family up on a posted flier that asked if there were any adults in the building who would play chess with their 6-year-old son.

"He was just a brilliant kid, always into computers, and I could see that he was going to be a star in whatever he did," said Mr. Brewer, who became something of an adopted uncle to Mr. Harrison, taking him to museums and art events as he grew.

Summers were also a big part of the early education of Mr. Harrison, as the family, later including his younger brother Ben, 19, would pack up and travel with his father to whichever continent -- Asia, Africa, Europe -- he was excavating.

Mr. Harrison remembers one summer in Borneo where, with few of the comforts of home, "I had to play with sticks as toys. So, you had to be creative."

The travels also taught him an invaluable lesson about where the differences and similarities exist between cultures.

"You see what people value, what they use technology for, how it affects them. And you realize, you can't just give everyone a laptop and think it will help. That's something I always keep in the back of my mind," he said.

Mr. Harrison also realizes that some people might think of Skinput as another step toward that quip about ever-smaller mobile devices: that the next step might just be a chip placed in our heads.

He's not a fan of that notion.

"No, we want to be human; we don't want to be cyborgs," he said. "I'm not saying let's get rid of buttons altogether. We've got to be careful about what we want to do."

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