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Researchers develop electronic nose for multimedia

01.04.2004

Imagine you are a thousand miles from home, and your mother cooks your favourite meal for you. Then she takes a photo of it and sends it to you by email. And then, when you open the photo, a wave of aroma--your Mom’s cooking--fills the air.

Two researchers at the University of Alberta have been working to make this type of scenario a reality. Their latest success, the development of an electronic nose for multimedia use, has been reported recently in IEEE Transactions on Consumer Electronics.

Dr. Mrinal Mandal, a professor in the U of A Department of Electrical and Computer Engineering, and Rafael Castro, a master’s student studying under Mandal, have developed an apparatus that will recognize the odors of ten different smell groupings--from fruits, to coffees, to gases, to spices and to just about everything in between. The device connects to a PC, which then determines what smell the electronic nose has captured.

So far, smell detectors have been developed and are currently used in various industry capacities, such as to detect cyanide gases and rotten fish--jobs that would make people sick or would be unpleasant, Mandal said. He added that these ’noses’ are expensive and wouldn’t be appropriate for multimedia use because they have been designed only to complete specific, narrowly defined tasks.

Mandal said that Castro built his electronic nose entirely with inexpensive electronic parts that can be found in any local hardware store.

"The nose works in a more complex way than the eyes do," said Mandal, explaining the challenges in building the system. "There are primarily three colour receptors in the human eye, but there are several million smell receptors in the nose and about 1,000 different types of receptors, so you need to create at least 1,000 smell channels to build a good electronic nose."

Mandal and Castro also ran into a few difficulties they didn’t expect. For one, the fact that smells--unlike visual images or audio signals--require the movement of molecules, means that smells can be sticky and can linger. To solve this problem, Castro devised a pump "cleaning system".

According to Mandal and Castro, the next step in order to add smell to the multimedia experience is to develop a low-cost smell generation system--a challenge Castro believes will be easier than it was to develop the smell capturing system.

Mandal, who has recently written a book on multimedia, envisions a mass-produced, said an inexpensive electronic nose may become available sometime in the next five to ten years. However, Mandal and Castro both say their interest in the research is more academic than commercial.

"It is a big challenge. And I love challenges," Castro said.

Rafael Castro can be reached at 780-492-0152 or rcastro@ualberta.ca.
Dr. Mrinal Mandal can be reached at 780-492-0294 or mandal@ece.ualberta.ca.