You might be familiar with the green horseradish paste that comes with sushi — wasabi. Scientists in Japan used the pungent smell of wasabi as an alarm to alert people of a fire. This idea seems incredible, but it was motivated by efforts to create an alarm system effective for people with hearing difficulties.
- Wasabi smoke alarm. Photo by Air Water Safety Service.
Japan’s news stations Asahi and NHK described the progress of this project from 2006 to 2008 (link to news in Japanese text). The basic structure of the alarm is as follows. A mix of wasabi and mints create a bitter and stinging smell that stimulates the mucous membrane within the nose. This smell is then collected into a pressurized can. When the fire alarm bell rings, the machine detects the sound and relays an electric signal to trigger the release of the wasabi smell.
Medical equipment manufacturers collaborated to produce this wasabi alarm. Experiments conducted by the Shiga University of Medical Science illustrated the efficacy of this wasabi alarm to wake up people who are sound asleep. For a subject pool of 14 males and females in their 20s to 40s, the researchers found that except for one person who had a stuffy nose, all other 13 people woke up within 2 minutes. Four of these subjects had a hearing impairment, and these people woke up within thirty seconds. The fastest record-response was ten seconds. After experiencing the pungent smell, the test subjects strongly supported the implementation of this wasabi alarm device.
This invention received international attention in the Ig Nobel Prize and in news reports by BBC and Reuters. The following video shows BBC’s report on the wasabi alarm.
Other fire alarm systems made for the deaf have used light and vibrations but with mediocre success. Light is hard to notice while asleep, and vibrations require the machine to be worn by the person at all times to detect any movement. Researchers hope that this wasabi alarm system would be used effectively in conjunction with these earlier alarm systems.
“Achievements that first make people laugh, and then make them think” is the core principle of the Ig Nobel Prize. The humorous aspect of the wasabi alarm caught my attention. However, I soon started to question the use of such an invention, and this curiosity directed me to read about the weaknesses of a sound-based alarm. This research for sure made me think.