Japanese researchers have developed head gear that uses infrared sensors and a microcomputer to let people operate music players by clenching their teeth.

Japanese train commuters who don't want to reach conspicuously into their bags or pockets to start their iPods will soon be able to do it more subtly -- by simply clenching their teeth.

Japanese researchers have developed head gear that uses infrared sensors and a microcomputer to let people operate music players by clenching their teeth.

The computer receives a command when the user clenches his or her teeth for about one second -- which differentiates the action from other activities such as chewing gum and talking.

The research team at state-run Osaka University hopes to put the device to commercial use for music players and believes it can eventually be adapted to run cellphones, wheelchairs and other products.

"You are able to operate the devices without using your hands," said Fumio Miyazaki, an engineering science professor who heads the laboratory working on the project.

"You would be able to listen to music hands-free or operate your cellphone in a crowded train. Handicapped people would also be able to move wheelchairs," he told reporters.

Kazuhiro Taniguchi, who is playing a leading role in the research, said the system can be used by anybody who can chew food with their teeth -- real or artificial.

"I just thought it's inconvenient" to have to use your hands to switch on iPods or phones, especially on packed trains, Taniguchi said.

In the laboratory, grinding right teeth can play and halt music on an iPod while clenching left teeth makes it skip to the next track, he said.

The system could also allow users to flip through pages of a PowerPoint demonstration, allowing the presenter to gesture freely by clenching teeth instead of pressing buttons.