The next time you are on a train in Japan and the person next to you starts gnashing their teeth, don’t worry. . . They may simply be working their controls on their iPod.

Researchers at Osaka University have developed a headset that employs infrared sensors and a microcomputer that makes it possible for people control their digital audio players by clenching their teeth – grinding the right molars will start or stop playback, while clenching the left molars skips to the next track.

The microcomputer differentiates between control clenches and other activities such as chewing gum and talking by analyzing duration. The wearer must clench for at least one second to send a command to the iPod.

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.

The developers say the system also could be used for hands-free control of the slides of a PowerPoint presentation.