The “Smellicopter” Drone will Literally Sniff it’s way around the Surroundings.
Researchers from the University of Washington have developed an autonomous drone that uses a live moth antenna to seek out smells in its surroundings.
There is considerable interest in developing drones that could detect chemicals in the air, locating disaster survivors, gas leaks, explosives, narcotics, and other interest objects.
However, most human-made sensors are not sensitive or fast enough for these applications.
The University of Washington engineers worked around this by incorporating a live antenna from a moth to create a drone to navigate towards smells.
“Nature blows our human-made odor sensors out of the water,” said mechanical engineer and Ph.D. candidate Melanie Anderson.
“By using an actual moth antenna with Smellicopter, we’re able to get the best of both worlds: the sensitivity of a biological organism on a robotic platform where we can control its motion.”
Moths use their antennae to detect chemicals in their surroundings and navigate towards food sources or potential mates: “Cells in a moth antenna amplify chemical signals.
Rare m it efficiently – one scent molecule can trigger lots of cellular responses, and that’s the trick. This process is super-efficient, specific, and fast,” said Professor Thomas Daniel, a University of Washington biologist.
The researchers used antennae from the Manduca sexta hawkmoth; they placed live moths in the fridge to anesthetize them before removing an antenna.
Once separated from the moth, the antenna remains biologically and chemically active for up to four hours.
The antenna was wired into a circuit so that the researchers could measure the average signal from its cells.
They compared it to a typical human-made sensor by placing both in a wind tunnel and wafting various smells into the tunnel; the antenna reacted and recovered more quickly than the conventional sensor.
It then incorporated the antenna sensor into an open-source quadcopter drone platform, allowing users to add custom features, creating Smellicopter.
Two plastic fins were attached to the back of the drone to orient it upwards during flight.
The researchers created a “cast and surge” protocol for the drone, which mimics how moths search for smells.
Smellicopter begins by moving to the left for a specific distance. If nothing passes a certain smell threshold, it moves to the right for the same distance. When it detects an odor, it changes its flying pattern to surge towards the source.
Smellicopter can also avoid obstacles with four infrared sensors, which scan their surroundings ten times per second.
When an object is within 20cm of the drone, it changes direction by moving to the next stage of its cast-and-surge protocol.
“So, if Smellicopter was casting left and now there’s an obstacle on the left, it’ll switch to casting right,” said Anderson.
“And if Smellicopter smells an odor but there’s an obstacle in front of it, it’s going to continue casting left or right until it’s able to surge forward when there’s not an obstacle in its path.”
In lab-based tests, the drone naturally flew towards smells that moths find interesting, such as floral scents.
However, the researchers hope that in the future, it could be adapted to detect other scents, such as carbon dioxide or the chemical signature of an unexploded device.
“Finding plume sources is a perfect task for little robots like the Smellicopter,” said mechanical engineer Professor Sawyer Fuller. “Larger robots are capable of carrying an array of different sensors around and using them to build their world.
We can’t really do that at the small scale.”
“But to find the source of a plume, all a robot needs to do is avoid obstacles and stay in the plume while it moves upwind.
It doesn’t need a sophisticated sensor suite for that – it just needs to smell well. And that’s what the Smellicopter is good at.”