Airdropping sensors from moths: Researchers use flying bugs to drop sensors from air, land them safely on the bottom

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Engineering | Press releases | Research | technology

October 8, 2020

UW researchers have developed a sensor system that can ride on a moth’s back. Here a Manduca Sexta moth is shown with the sensor on its back.Mark Stone / University of Washington

There are many places in this world that are difficult for researchers to study, mainly because it is too dangerous for humans to get to.

Now researchers at the University of Washington have come up with a possible solution: a 98-milligram sensor system – about a tenth the weight of a jelly bean or less than a hundredth of an ounce – that can ride aboard a small drone or an insect like a moth, until it reaches its destination. When a researcher sends a Bluetooth command, the sensor is released from its perch and can fall and land up to 72 feet – say, from the sixth floor of a building – without breaking. Once the sensor is on the ground, it can record data such as temperature or humidity for almost three years.

The team presented this research on September 24th at MobiCom 2020.

“We have seen examples of the military dumping food and vital supplies from helicopters in disaster areas. We took inspiration from it and asked the question: Can we use a similar method to determine the conditions in regions that are too small or too dangerous for a person? Said senior author Shyam Gollakota, an UW Associate Professor at the Paul G. Allen School of Computer Science and Engineering. “This is the first time anyone has shown that sensors can be released by tiny drones or insects like moths, which can fly through tight spaces better than any drone and withstand much longer flights.”

While industrial-size drones use grippers to carry their payloads, the sensor is held to the drone or insect using a magnetic pen surrounded by a thin wire coil. To release the sensor, a researcher on the ground sends a wireless command that creates a current through the coil to create a magnetic field. The magnetic field makes the magnetic pen pop out and sends the sensor on its way.

The sensor was constructed with its battery, the heaviest part, in a corner. If the sensor falls, it will turn the corner with the battery, creating extra drag and slowing down the descent. Combined with the low weight of the sensor, the maximum fall speed remains at 11 miles per hour, so the sensor can safely hit the ground.

The sensor system (shown here on a penny above) was designed with its battery in a corner (shown here as a disk on the left). If the sensor falls, it will turn the corner with the battery, creating extra drag and slowing down the descent.Iyer et al./MobiCom 2020

The researchers intend to use this system to create a sensor network within a study area. For example, researchers could use drones or insects to scatter sensors over a forest or farm that they want to monitor.

Once a mechanism to restore sensors after the batteries are discharged is developed, the team believes the system can be used in a wide variety of locations, including environmentally sensitive areas. The researchers plan to replace the battery with a solar cell and to automate the use of sensors in industrial environments.

A drone flies and carries a small sensor chip underneath.

The sensor system can also be carried by a small drone. The drone shown here is a commercial quadcopter that was used in the experiments.Mark Stone / University of Washington

Vikram Iyer, PhD student in electrical and computer engineering; Maruchi Kim, a PhD student at Allen School; Shirley Xue, a PhD student at Allen School; and Anran Wang, a graduate student at Allen School, are also co-authors of this paper. This research was funded by the National Science Foundation.

Contact sensordrop@cs.washington.edu for more information.

License numbers: CNS-1812554, CNS-1452494, CNS-182314

Day (s): College of Engineering • Paul G. Allen School of Computer Science and Engineering • Shyam Gollakota