Northwestern University engineers have created microchips that can fly. They're about the size of a grain of rice, and they don't have a motor or engine.
Instead, they catch wind currents and spin like a helicopter, not unlike the propellor seeds on maple trees.
That was one of the inspirations behind the design, along with other variations of wind-dispersed seeds.
As the microfliers fall through the air, their wings interact with the current to create a slow and stable rotational fall. The data they collect can transmit to a phone, tablet, or computer.
"Over the course of billions of years, nature has designed seeds with very sophisticated aerodynamics," John A. Rogers, a Northwestern engineer who led the microchip's development, said in a statement.
"We borrowed those design concepts, adapted them, and applied them to electronic circuit platforms.”
Human-made structures with their bio-inspiration: 3D microfliers with a propeller leaf. Caption and photo: F. Frankel
The team hopes the microchips will one day monitor our environment by measuring air pollution levels and tracking airborne diseases.
"In the lab, Rogers’ group outfitted one device with all of these elements to detect particulates in the air," the study authors wrote.
"In another example, they incorporated pH sensors that could be used to monitor water quality and photodetectors to measure sun exposure at different wavelengths."
To date, they are the smallest-ever man-made flying structures, the team says, and can be fitted with antennas for wireless communication, as well as sensors and power sources.
A 3D microflier next to a pencil tip for scale (Rogers et. al)
WHAT ABOUT LITTER?
Rogers says the chips aren't likely to cause a buildup of waste because they are created with electronics that "harmlessly dissolve" in water after use.
“We fabricate such physically transient electronics systems using degradable polymers, compostable conductors, and dissolvable integrated circuit chips that naturally vanish into environmentally benign end products when exposed to water,” Rogers said.
“We recognize that recovery of large collections of microfliers might be difficult. To address this concern, these environmentally resorbable versions dissolve naturally and harmlessly.”
The research is featured on the September 23 cover of the journal Nature.