NTT Docomo Inc developed earphones that detect the movement of eyeballs and exhibited them at CEATEC JAPAN 2009, which runs from Oct 6 to 10, 2009, at Makuhari Messe in Chiba Prefecture, Japan.
"We developed the earphones as a new hands-free user interface," the company said.
NTT Docomo made a demonstration of using the earphones to detect eyeballs moving from side to side and up and down and operating a music player and a mobile phone.
"The corneal side of an eyeball is positively charged while the retinal side is negatively charged," the company said. "In the medical field, the movement of eyeballs is detected by attaching electrodes around the eyes. We applied that technology to earphones."
The new earphones have electrodes around its speakers, and the movement of eyeballs is detected by the change in voltage at the electrodes.
According to NTT Docomo, the signal-to-noise (S/N) ratio lowered by about 95% compared with the case of the electrodes attached around the eyes. Therefore, the company improved the signal processing system of the earphones so that it can detect the movement even at such a low S/N ratio.
In the demonstration, when the eyeballs moved from right to left, the music player started to play music (and paused when the music is being played). When they moved to right twice, the player skipped a track. And when they rotated clockwise, the volume increased.
"This time, we used a PC to carry out the process of detecting the movement of eyeballs from the change in voltage," NTT Docomo said. "But the required throughput is not high. And processors equipped in existing mobile phones will be enough."