In an innovative solution to the problem of deaf people not being able to hear fire alarms, Japanese researchers have developed one that sprays the strong smell of horseradish, ensuring that everybody with a functioning sense of smell wakes up. In tests, it successfully, silently woke up 13 out of 14 people, with deaf subjects much more receptive to the alarm. Combine this with an audible alarm and a small robot that goes around slapping people in the face and you’ve got yourself one foolproof fire alarm. [WCTV via Boing Boing]