Tiny sensors with a design inspired by dandelion seeds could be scattered to the winds to help track key indicators of climate change and global warming.
As the climate crisis continues to intensify, tracking changes in temperature, humidity and other environmental signals across a wide area is useful. But doing so effectively requires dispersing sensors throughout the environment, which can be time-consuming.
“Rather than having a person go out and individually place sensors, which can be dangerous in hard-to-reach places where we’d like to do these measurements, we wondered whether it’s possible to build a system that can disperse sensors in the wind,” says Vikram Iyer at the University of Washington in Seattle.
Iyer and his colleagues used a laser-powered tool to manufacture devices from polyimide films. Each one weighs 30 milligrams with a diameter of 28 millimetres, and carries an array of small holes through which air can pass to allow it to float in the air like a dandelion seed.
The devices carry tiny sensors – essentially a microcomputer powered by minute solar panels – that can send back signals to the researchers, who developed different types that measure temperature, humidity, pressure and light. A small on-board capacitor can store energy overnight or in cloudy conditions
In all, the team tested 75 different designs before finding the optimal mix of variables. The final design can move through the air at 0.87 metres per second, travelling up to 100 metres in a moderate breeze when released from a drone. Real-world tests showed that the sensors can transmit data up to 60 metres.
“The fabrication of the ‘seeds’ is especially interesting, as is the design of the electronics,” says Jonathan Aitken at the University of Sheffield, UK. “Both seem to be very robust to the natural environment.”
Aitken is also impressed by the range of the sensors’ communication abilities. “Coupled with the cheapness of the device meaning that it can be deployed in large numbers, [the communication range] makes this an excellent option, especially within farming or disaster area monitoring,” he says.