This drone sniffs smells with an actual moth antenna
Anderson and her colleagues went a step further and programmed the smellicopter to chase scents, just like a real moth would. If you are able to smell an odor, there is a good chance the source is upwind from you. The same goes for insects like moths, which do something like crosswind casting, in which they attach themselves to a source believed to be upwind and fly towards it, then move their bodies left or right as needed to focus on the scent to stay. Anderson’s team trained the smellicopter to do the same. “If the wind changes or you deviate a little, you lose the smell,” says Anderson. “And so you throw cross winds to try to take up that path again. In this way, the smellicopter gets closer and closer to the source of the odor. “
The researchers call this a “cast-and-surge” algorithm: the drone moves in the direction of an odor – they used a mixture of flower compounds in the laboratory – and reaches left or right when it loses the odor and then jumps after it in front as soon as it is stuck again The drone is also equipped with laser sensors that allow it to detect and avoid obstacles while sniffing around.
And boy, does it work well: the researchers found that 100 percent of the smellicopter gets to the source of an odor. This is in large part due to the extreme sensitivity of the moth antenna, which can detect tiny smells not on the order of parts per million or billions, but trillions. A moth uses physics to further increase its efficiency: when it flaps its wings, it circulates air over its antennae, helping to capture more odor. Again, the researchers were inspired by nature and used the spinning blades of the quadrotor to move more air over their borrowed antenna.
Sure, right now, humanity may not have much of a mind for a moth drone sniffing flowers. Therefore, the researchers are looking for ways to use gene editing to create moths with antennae that smell like bombs. But could these Franconian moths be just as sensitive to the smells of man-made materials as normal moths are to the pheromones of potential partners and the smell of flowers? That is, can researchers readjust a sense of smell that evolution has perfected for the moth over hundreds of millions of years of evolution?
“In theory, you could become more sensitive,” says Anderson, “because the moth antenna can sense a variety of different chemicals, much like we can smell a variety of different things.” The idea of her laboratory would be to genetically engineer a moth antenna so that it is full of the special protein that plays a role in detecting a desired chemical. That would focus the antenna’s performance on one smell, not many.