It’s a moth, a drone, a “Smellicopter”

Melanie Anderson puts a small curtain aside in a dark closet. The only light is a dim red light bulb.

“I want to catch a male moth, so this may take some time,” she says, reaching for the cage behind the curtain.

She pulls out a mottled brown Manducase xta. This is sometimes called Carolinasphinxmoth. It’s big — bigger than her palm.

“It looks like a woman. The antenna is a bit small,” she says. “So I’m going to put it back.”

Antennas are key to this University of Washington engineer.

Anderson reaches the fluttering mass of insects in the cage once and then twice. She finally caught the man.

This moth’s antennae is destined for a cyborg on a new type of drone called the “Smellicopter”.

“I tell people” moth antennas “, and they” what does “moth” stand for? It’s like. And I explain, “No, no, no. Insects.” “We actually use an antenna, which is a living biological component of a moth, and place it in an electrical circuit to read the signal.”

But Smellicopter is more than just state-of-the-art biohybrid technology, it’s an innovation that can make us safer in the face of accidents and disasters.

Super smell

The antennae of moths are a masterpiece of the evolution of the sense of smell. They can pick up a faint scent.

“Biology can detect chemicals at levels well above synthetics. It’s not a factor of 1000, 10,000, 100,000, or even a million. It’s even bigger,” said Tom Daniel, a biologist at Washington University. Said. “So we used the extreme sensitivity of odor detection in a living system and asked,’How can we integrate it into a synthetic system?’ “

Daniel, head of a consortium of researchers studying nature-inspired flight systems, asked Anderson this question, and she earned her PhD. Answer it.

Anderson and her research partner Joseph Sullivan have created a drone that harnesses the extraordinary sensory power of a moth’s antenna.

“We can install it in a chemical plant to explore the area and find the cause of odor and gas leaks very quickly before it gets out of hand,” Anderson said. “It can be used in place of search dogs in dangerous situations, or to search and rescue workers, so it can really save lives.”

It works by combining biology, robotics, coding, aerodynamics, and many other disciplines into one device.

After cutting the antenna from the anesthetized moth, Anderson uses tweezers to thread the hollow structure through the hair-like wire of the circuit.

“She can manipulate that antenna to put that little silver wire in it, and she doesn’t even need a table — I can’t,” Sullivan sees Anderson’s stable hand. I say.

“Give a picture of Warhammer for a few more months and you’ll get the same dexterity,” Anderson replies.

She bends the antenna and tramples the other end on the opposite wire. The antenna loop completes the circuit.

When a moth’s antenna encounters a particular odor, it reacts and produces a faint signal that runs between the two wires.

“We are measuring the electrical activity of the antenna, which is very weak,” says Sullivan.

Some moths eat nectar from flowers, so their antennae are highly tuned to their scent.

“It can react to shampoos and conditioners, especially if you’ve just taken a shower,” she said.

The reaction can be seen on the line graph on her computer. In the surrounding air, the line is fairly stable. However, when Anderson blows the scent of flowers throughout the antenna, spikes occur. These spikes inform the drone that the source of the odor is nearby.

Such “electroanthenogram” odor sensors have been around for a long time, but they are new to attach to drones for use in disaster areas.

Inspired by nature

The idea for Smellicopter came from the Center of Excellence of the US Air Force on naturally inspired flight techniques and ideas. This group consisted of scientists and engineers from several universities.

Mark Willis, a biologist studying moths at Case Western Reserve University in Ohio, said: “If you think about it, flight is a kind of movement where everything is happening fast … If you can’t make quick adaptations, you’ll hit something.”

Willis is a member of Center for Excellence, but was not directly involved in the creation of the Smellicopter.

He said artificial odor sensors are currently unable to respond fast enough to meet flight requirements. However, moth antennas are ideal because they have a response interval of less than 100 milliseconds and can respond quickly and continuously to odors in the environment.

“Smellicopter is actually a great example of the first step in the busy process of coming up with a synthetic odor detector that removes itself as quickly as a biological odor detector. All you have to do is take it and hit it against the robot, “says Willis.

Smellicopter’s connection to nature is even more advanced than a living antenna. Anderson drones also look to moths to stimulate how the drone flies.

“When a moth smells … it soars upwind. And when the wind changes or it goes off course a little, and it loses its scent, cast a crosswind back and forth until it smells again. And they soar upwind again, “she said.

A small wind tunnel on campus is testing Smellicopter’s cast and surge strategies. Anderson drops a drop of floral scent on the head of the tunnel and fires a small drone.

Smellicopter flies back and forth looking for trails. It is trapped and soars towards the scent.

“At that time, it went directly to Sauce. There were a lot of hits in that last surge,” Anderson tells Sullivan.

“Yes, that’s right. Peak. Peak. Peak. Peak. Peak.”

The next evolution of Smellicopter

If gas leaks, buried victims, and explosive devices all smell like flowers, Smellicopter is a business.

But that’s not the case. And that is the next big step in the evolution of Smellicopter.

“We are working on genetically manipulating moth antennas to detect a variety of chemicals … Amplify the antenna’s sensitivity to bomb scents, then flower scents, moths, etc. It removes sensitivity to unwanted things. Pheromon, “Anderson said.

This work is currently underway as Anderson’s postdoc at the University of Washington. She is also working on an electric antenogram attached to a cell phone that can be used as a handheld sensor.

Smellicopter is at the crossroads of new technology.

“We have device technology and neural recording technology that are robotics. There is gene editing. It’s a crazy and modern technology,” said Tom Daniel.

You can also get a glimpse of what would be possible if you added artificial intelligence to your mix. You can hear all of them at once, not just one signal from the moth’s antenna.

“There are many cells in an antenna circuit that enter an animal, each signaling a different chemical. Can we use machine learning to identify” is it Tom? “? Or “is it you?” I know my dog ​​can sniff our differences, “Daniel said.

“So, can we combine gene editing, device technology, and AI to create a sommelier?”

And if we could make such a sophisticated artificial sensor, there would be no limit to where the new nose could take us next.