Let Your Pupils Do the Typing
New submitter s.mathot writes: Researchers from France and the Netherlands have developed a way to—literally—write text by thinking of letters. (Academic paper [open access], non-technical blog, YouTube video.) This technique relies on small changes in pupil size that occur when you covertly (from the corner of your eye; without moving your eyes or body) attend to bright or dark objects. By presenting a virtual keyboard on which the 'keys' alternate in brightness, and simultaneously measuring the size of the eye's pupil, the technique automatically determines which letter you want to write; as a result, you can write letters by merely attending to them, without moving any part of your body, including the eyes.
I think that eye movement tracking have been studied for a long time as an input method, mostly for handicapped people that lacks movement in a major part of their body.
What about the system Stephen Hawking uses?
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.