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.

(AP) 乘火车通勤的日本人如果觉得把手伸进包里或口袋里开iPod太费劲，那么这一问题很快就能解决了——你只需咬咬牙就能启动iPod。

日本研究人员近日开发出一种内置红外线传感器和微型计算机的头套，通过这种装置，人们只需咬紧牙就能启动音乐播放器。

当人们咬紧牙约一秒钟时，微型计算机就能接收到一个指令。而这里所说的咬紧牙与嚼口香糖和说话等活动是不同的。

大阪国立大学的研究小组希望能将这一装置投入商用，用于音乐播放器，并相信这一装置经“改造”后，最终还能用于手机、轮椅和其它产品。

工程学教授、该项目的实验室工作负责人宫崎文雄说：“你不用手就能启动播放器。”

“以后在拥挤的火车上听音乐、摆弄手机，就不用手了。残疾人也能自己移动轮椅了。”

该研究的主要负责人谷口一浩说，只要能用牙（真牙假牙都可以）咀嚼食物的人就可以使用这一系统。

他说：“我只是觉得用手操作iPod或手机不方便，尤其是在拥挤的火车上。”

据他介绍，在实验室所做的实验中，咬紧右边的牙齿能够启动和停止iPod，咬左边的牙则能使播放器跳至下一个节目。

人们还能通过这一系统翻动PowerPoint演示页，这样演示者就可以腾出双手自由地做手势了，因为他们只需要咬咬牙，不用再按键了。