- The Engineers Behind the MicroFlyer Were Inspired by Maple Tree Seeds
- They float in the air, catching the wind and spreading them far and wide
- Newer devices contain a wide variety of devices, including sensors and power
- They can swim through the air gathering data on pollution levels or look for signs of airborne illness after a major outbreak and send the data back to scientists.
A microchip the size of a grain of sand is the smallest human-made flying structure ever built, according to its developers, who say it can track airborne disease.
Scientists say that the ‘microflyer’ can also be used to monitor air pollution and environmental pollution, which was not possible before.
There’s no motor involved—the tiny device acts like a maple tree’s propeller seeds, catching the wind and slowing its fall as it glide toward the ground.
By studying seeds dispersed in the wind, engineers at Northwestern University in Evanston, Illinois, optimized the aerodynamics of the microflier to ensure that when dropped from a height, it slows down in a controlled manner.
This allows for dispersal over a wider area and increases the time spent in the air, interacting with pollution and disease particles along the way.
So far, versions of smaller instruments have included air pollution sensors, equipment to study solar radiation at different wavelengths and a pH sensor to monitor water quality.
Man-made 3D microflyers surround a propeller seed from its nature-created inspiration, a maple tree. These tiny chips hold air as they glide through the air
A photograph of a 3D microflyer fitted with a circuit to measure fine dust pollution. Scientists say ‘microflyer’ can also be used to monitor air pollution and environmental pollution, which was not possible before
MicroFlyer: A Nature’s Beating Design
The swirling propeller of a maple leaf propels the seed through the air and gently descends onto the pavement guided by the wind.
This is just one example of how nature has developed clever, sophisticated ways to enhance the survival of various plants.
By ensuring that the seeds are widely dispersed, sedentary plants and trees can propagate their species over vast distances for populations in wide areas.
These biological structures are designed to collapse slowly and in a controlled manner, so that they interact with wind patterns over the longest period of time.
This feature maximizes lateral delivery through a purely passive, aerial mechanism.
To design the microflyer, the Northwestern team studied the aerodynamics of plant seeds.
Taking its most direct inspiration from the Tristeletia plant, a flowering vine with star-shaped seeds.
Tristeletia seeds have bladed fins that with a slow, reciprocating spin catch the wind as they fall.
He designed and built several different types of microflyer, including one with three wings, adapted to the same size and angles as the wings on Tristeletia seeds.
The resulting structures can be built in a variety of shapes and sizes, some qualities that can give nature a run for its money.
Lead engineer John Rogers said, ‘We think we have defeated nature.
‘At least in the narrow sense that we are able to build structures that fall with more stable trajectories and slower terminal velocities than similar seeds that you would see from plants or trees.
‘We were also able to build these helicopter flight structures at sizes smaller than those found in nature.
‘This is important because device miniaturization represents the dominating growth trajectory in the electronics industry, where sensors, radios, batteries and other components can be manufactured in ever smaller dimensions.’
The US team said the microflyer began life as a small-scale electronic system that could be loaded with sensors, and then made to fly – or at least glide.
As well as sensors, it has a power source, antennas for wireless communication, and embedded memory to store data, the team explained.
Bioelectronics pioneer Professor John Rogers, who led the development, said the goal was to use the tools to understand the environment for contamination monitoring, population monitoring or disease tracking.
The team drew inspiration from the biological world, which Prof Rogers said took billions of years to develop sophisticated aerodynamics.
Professor Rogers explained, ‘We borrowed those design concepts, adapted them and applied them to electronic circuit platforms.
‘These biological structures are designed to collapse slowly and in a controlled manner, so that they interact with wind patterns over the longest period of time.’
To design the microflyer, Prof. Rogers and his colleagues studied the aerodynamics of the seeds of several plants, its most direct inspiration being Tristeletia, a flowering vine containing star-shaped seeds.
He explained that Tristeletia spores have wings that with a slow, revolving spin catch the wind as they fall.
Part of the work involved the design and development of several types of microflyers, including one with three wings, adapted to the angles of Tristeletia.
To pinpoint the most ideal structure, Professor Yonggang Huang, who led the study’s theoretical work, conducted computational modeling of how air flows around the device to mimic the slow, controlled rotation of Tristeletia seeds.
Based on this, Prof. Rogers’ group then built and tested the structures in the laboratory, using advanced methods for imaging and measuring flow patterns.
The resulting structures can be built in a variety of shapes and sizes, with some qualities Prof Rogers says could give nature ‘a run for its money’.
The chief engineer declared, ‘We think we have defeated nature.
‘At least in the narrow sense that we are able to build structures that fall with more stable trajectories and slower terminal velocities than the equivalent seeds that you will see…