Smellicopter makes use of moth antenna to detect risky chemical compounds


A moth antenna was used to create a smellicopter, a small autonomous drone designed to detect chemical signatures that indicate explosives or people trapped after a natural disaster.

The researchers are interested in developing devices that can help in these dangerous situations. However, most sensors aren’t sensitive or fast enough to find and process certain smells as they fly through the mottled feathers these sources create.

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The smellicopter of a team led by the University of Washington uses the live antenna of a Manduca Sexta Hawkmoth to navigate towards scents. Smellicopter is said to be able to detect and avoid obstacles on its way through the air. The team’s results will be published in IOP Bioinspiration & Biomimetics.

“Nature really blows our man-made odor sensors out of the water,” said lead author Melanie Anderson, a UW graduate student in mechanical engineering. “By using a moth antenna with a smellicopter, we can get the best of both worlds: the sensitivity of a biological organism on a robot platform on which we can control its movement.”

The moth uses its antennae to sense chemicals in its environment and to navigate to food sources or potential partners.

“Cells in a moth antenna amplify chemical signals,” said co-author Thomas Daniel, a UW professor of biology who supervised Anderson’s doctoral thesis. “The moths do this really efficiently – a scent molecule can trigger a lot of cellular responses, and that’s the trick. This process is very efficient, specific and fast. “

The researchers put moths in a refrigerator to numb them before removing an antenna. Once separated from the living moth, the antenna remains biologically and chemically active for up to four hours.

By adding wires to both ends of the antenna, the researchers were able to connect it to a circuit and measure the average signal from all cells in the antenna. The team then compared it to a typical man-made sensor by placing it both at one end of a wind tunnel and with wafting smells – a floral scent and ethanol – to which both sensors would respond. The antenna responded faster and took less time to recover between pulls.

To develop smellicopters, the team added the antenna sensor to a standard quadcopter and placed two plastic ribs on the back so that it could be constantly pointed against the wind.

A team led by the University of Washington has developed Smellicopter: an autonomous drone that uses a live antenna of a moth (brown arch above the drone) to navigate towards smells (Image: Mark Stone / University of Washington)

“This is a genius from a robotics perspective,” said co-author and consultant Sawyer Fuller, a UW assistant professor of mechanical engineering. “The classic approach in robotics is to add more sensors and possibly create a fancy algorithm or use machine learning to estimate wind direction. It turns out that all you have to do is add one fin. “

The team created a “cast and surge” protocol for the drone, mimicking the way moths search for scents. Smellicopter begins its search by moving left for a certain distance. If nothing exceeds a certain odor threshold, the Smellicopter will move the same distance to the right. As soon as it detects an odor, it changes its flight pattern to approach it.

Four infrared sensors help smellicopters avoid obstacles. If something is within about 8 inches of the drone, it changes direction by moving on to the next stage of its cast and surge protocol.

“So if Smellicopter has thrown to the left and there is now an obstacle on the left, it will be thrown to the right,” Anderson said in a statement. “And if the Smellicopter smells a smell but there is an obstacle in front of it, it will keep throwing to the left or right until it can shoot forward if there is no obstacle in its path.”

Instead of GPS, Smellicopter uses a camera to monitor the environment. This should make the drone well suited for exploring indoor or underground spaces such as mines or pipes.

During the tests in the UW research laboratory, the Smellicopter was of course tuned to fly for smells that moths find interesting, such as B. floral fragrances. The researchers hope that future work with the moth antenna could detect other smells, such as the exhalation of carbon dioxide from someone trapped under rubble or the chemical signature of a device that has not exploded.

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