Sniffing in Machine Olfaction
Machine Olfaction aims to develop electronic noses that detect and recognize odors in the air. You could imagine that such devices might be useful in anything from finding bombs, to determining if the milk has gone bad. Sniffing is an important part of a dogs sense of smell, but electronic noses have only just started using sniffing to draw more odors into the device. We have developed an electronic nose that mimics sniffing and are investigating how to process the data so that our nose can distinguish between different odors. This can be challenging with the sniffing because the airflow is constantly changing between inhaling and exhaling.
Electronic noses have an advantage over electronic tongues in that noses don’t need to make direct contact with the chemical source. When an electronic tongue makes contact with a chemical, it potentially exposes the sensors to harmful substances that could damage the device. It’s like how in chemistry class, you’d never lick any of the chemicals. That would be bad for your health. Instead, you were instructed to waft the chemicals towards your nose. We would like to do something similar in replacing electronic tongues with electronic noses, protecting the device from overexposure to harmful substances. The problem is, electronic noses do not work underwater, while electronic tongues do. Luckily, the star-nosed mole has found a way to employ its own nose to sniff out prey underwater. They blow bubbles onto rocks, then quickly suck the bubble back in, before the bubble floats away, to pick up a scent. We suspect that the star-shaped structure surrounding their nostrils plays a role in keeping the bubble centered on the nostrils to be sucked back in. My research is on how this star structure prevents the bubbles from floating away. We hope that this research can inspire some sort of star-shaped attachment that will allow our own electronic nose to sniff for chemicals underwater.