Rolling your eyes to turn up the volume on a portable music player and tapping your fingers to turn on a DVD player are among technologies Japan's top mobile carrier is testing to make "wearable" gadgets.
In one version, sensors and chips inside headphones detect electrical current produced by the movements of the wearer's eyeballs, said Masaaki Fukumoto, executive research engineer at NTT DoCoMo.
"We are working on a cell phone of the future," he said at a suburban Tokyo research center.