Imagine a robot playing soccer on a field no bigger than the period at the end of this sentence. When it scores a goal, it does a happy dance.

That's what a group of eight uber-smart undergraduate students at the University of Waterloo is working on.

They're building the world's smallest radio-frequency-controlled robot. Measuring 300 microns by 300 microns, their robot will be the width of two human hairs.

"One millimetre is the smallest unit on your ruler," says Ivan Law, one of the nanotechnology and mechatronics engineering students on the team. "If you divide that by three, that's how long our device will be."

Soccer is the fun application for this multi-disciplined venture, aimed at winning the RoboCup Nanogram soccer competition in Australia next July.

Far more serious are the real-world possibilities. If team members can pull this off, and they're confident they can, it means they'll have an air-propelled, radio-controlled robot that can move with minimum disturbance to, say, you. "If we put it into somebody's veins or blood vessels, it won't be disturbing the biological system," says the team's founder, Keith Peiris.

It could help in the fertilization of an egg, or in the identification of a serious bacterial infection.

It will work "almost like a car with a balloon on it, in that we're displacing air to push a device in different ways," Peiris said. "What we're trying to do is take the technology in radio-controlled cars and create an antenna so that we can control it remotely using a laptop.

"We're trying to do it. . . wirelessly, and part of doing that is having a really, really tiny antenna that we can first of all fit into that tiny robot," Peiris said.

But first things first: to win the competition, the group's robot must dash across the infinitesimal soccer pitch, manoeuvre around pylons, pick up balls, put a ball in the net, and even execute a happy dance. A microscope and video camera will help contestants watch the action on the field.

The pioneering University of Waterloo Nanorobotics Group intends to be the first team in North America to complete all of the challenges in the competition, setting a new precedent in nanorobotics.

At 20 years of age, Peiris and Law are not your average whiz kids. Peiris started his own web firm when he was 11 years old. He's the chief executive officer of Cyberteks Design, which employs his dad and four others. It developed the Kitchener Rangers website. In 2006, Peiris was one of Canada's Top 20 Under 20.

Law, originally from Hong Kong, plays clarinet and saxophone, and is a member of the university jazz band. He's the group's politely tenacious promoter.

They've already done the unlikely.

They've convinced professors, experts in their fields, to do work with undergraduates that they would normally do with graduate students. They've formed, at their own initiative, what they believe is the only undergraduate research team in Ontario.

"The idea of making a tiny nanorobot in undergraduate studies is pretty far-fetched," admits Peiris, who hand-picked some of the team members from his classes. But "what we're doing is cutting-edge research and we want to be treated like researchers."

When Peiris approached associate professor Mustafa Yavuz a year and a half ago, the director of the nano and microsystems lab hesitated.

"Normally, the faculty doesn't want to have undergraduate students handle or deal with the equipment because these are worth multi-million dollars," Yavuz said.

But Yavuz had never met undergrads like these. He agreed to be their chief adviser, and recruited other scientists to help. "I felt the students are very serious because they are sacrificing to spend their extra time on the project. They have a very, very heavy curriculum."

He also worried that if UW didn't help them, they might look somewhere else. Or they might join the private sector. "I want to keep them in academia. They're good for Canada's science research."

The project is drawing on sponsorships from local companies, including Research In Motion. They're still looking for a sponsor to place the world's smallest ad on the robot. The teeny ad would easily beat a record set by IBM, which put a logo on a bee's knees, Peiris says.

The students -- Edgar Cao, Michael Kwan, Julianne Kline, Nabil Faruk, Rohan Mahimker, Syed Afzal, Peiris and Law -- are spending every minute they can on the project which began as a "napkin design." In addition to a heavy load of classes and co-op work, each one spends at least 30 hours a week on it, Peiris said.

They're not afraid to take risks, and they're not afraid to fail. But they don't think they will. "Based on our simulations we think this is a very big idea that can not only win this competition but have many applications in the real world, "Peiris said. "We're ready to build."