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Do you know how your nose works? To
understand how we smell, you first have
to realize that all objects around us
"shed" little pieces of themselves
called molecules. These molecules
float around in the air, where they can
then enter our nose and flow across
cilia, tiny 'nose hairs' for our nose cells.
These cells are covered in slimy
mucous for capturing smell molecules,
and once captured, they react with
another special kind of molecule, called
receptors, that are in the cilia. Each
patch of cilia have different receptors,
and so different smells trigger different
cilia. The nose cells then send this
information through the Olfactory Bulb
(mind you this is not a factory for old
light bulbs) to the brain, where smells
are recognized by the patterns of cilia
that they trigger. And voi la, you can tell
the difference between week old potato
peels in the trash can and the roses
blooming in your garden.

The Pocket Knows works very much
like how your own nose works. It has
"nostrils" for sucking in smell
molecules, just like the human nose
does. These molecules then flow over
electronic "cilia," which are actually
arrays of organic polymers. Different
patches of polymers react to different
smell molecules, and send an
electrical signal to the brain of the
Pocket Knows, a powerful set of
microprocessors. Here, the pattern of
polymers that reacted are compared
to lots of other patterns that are stored
in its memory, and once it finds a good
match, voi la, it recognizes a smell. A
person using the Pocket Knows can
even pogram it to detect bad foods,
stuff that cause allergies, and anything
else they'd want to avoid. And if the
Pocket Knows smells any of these, it
will beep and flash a warning. Just
think, before we could get the
technology for our Pocket Knows, we
first had to "know" our own nose first!