Microsoft Chairman Bill Gates bobbed his head to the Bee Gees as a South Korean student danced in front of a computer, demonstrating a program that measures whether a user is performing exercise movements correctly.

"That's great. I think I could use this one," Gates said.

Later, he tried on a visor, part of a system called Docterra, designed by a team of Japanese students to help doctors and patients communicate clearly and avoid medical errors.

Gates also tested a pair of vibrating wristbands that work with radio-frequency identification and mapping technologies to give blind people tactile cues to guide them where to turn right or left. The Brazilian team behind the project presented Gates with a green-and-yellow soccer jersey at the end of its presentation.

For Gates, each of these encounters Wednesday was a chance to identify with the budding programmers, all finalists in Microsoft's Imagine Cup contest, a global competition among college students using the company's software-development tools to advance health care.

"I got my start in computing as a developer," Gates said, recounting to the students his early experiences learning what software could do, and the thrill he got making it perform faster and better. "That's what really got me almost addicted to working with computers."

The competition's theme appealed to Gates, whose foundation focuses on global health and education.

"Obviously, around the world there's incredible unmet needs in health care, whether it's gathering data or assisting people, or software that's going to help with the new drug discovery taking place," he said.

Ivan Cardim, a 22-year-old from the Federal University of Pernambuco, Brazil, said after working on his team's Virtual Eye project, he could better understand Gates' decision to make the transition in two years from full-time work at Microsoft to full-time work at the Bill & Melinda Gates Foundation.

"After this work with blind people, you see how it's contagious. You start it and you don't want to stop," said Cardim, whose team was inspired to create technology to assist blind people by his grandfather, who is losing his vision.

Cardim's love affair with computers paralleled Gates' in some ways. They both were first exposed to computing in their early teens and had to snatch computer access where they could: In the early 1970s, Gates grabbed computer time, often at night, on scarce computers that were "about a million times less powerful than the personal computers that you're writing software on today," he told the students.

Cardim had to sneak time on his dad's machine.

"My dad would say, 'No! It's for me to work. Get away from it,' " he said. "I just usually used it hiding from him. Then after a while he just let me use it."

The Imagine Cup — and Gates' meeting in Redmond with seven of the 76 teams scheduled to compete in the finals later this summer in India — serves several purposes for Microsoft and the students involved.

Sanjay Parthasarathy, Microsoft's corporate vice president of developer and platform evangelism, said it's a chance for the students to gain confidence and see their ideas turn into a usable application. Past Imagine Cup teams have launched businesses around their projects.

For Microsoft, it's a chance to gather feedback on its tools for software developers.

"We learn so much when they do stuff and something didn't work quite right," Parthasarathy said.

It's also a recruiting opportunity for the company. Several top technical executives came by to review the students' projects, including Craig Mundie, who is moving into Gates' role overseeing research and incubation work.

Gates told the students their programming skills are in short supply around the world.

"We're certainly always looking for great developers," he said.

Benjamin J. Romano: 206-464-2149 or bromano@seattletimes.com