This nifty little device goes behind your ear and vibrates when it detects you are falling asleep by measuring the speed of head movements (head nodding, etc.). Perfect for boring classes, drives, and work. It costs only $15 (1,800 yen).
“With the Nap Alarm, waking up 15 minutes before said exam may be a thing of the past, though falling asleep while driving is another matter entirely.”
[via Gizmodo]