Imagine an array of wireless sensors with the ability to monitor how temperature, humidity or other environmental conditions vary across large swaths of land, such as farms or forests. Such a innovation could help to revolutionize agritech and other related technological fields.
Such sensors hold the possibility of providing new insights for a variety of applications, such as digital agriculture and for other important applications like monitoring climate change. However, these devices are time-consuming and expensive to operate, particularly where they need to be place physically positioned across a large area (and where hundreds of sensors would be needed).
There is a solution: Inspired by how dandelions use the wind to distribute their seeds, researchers from University of Washington have developed a tiny sensor-carrying device that can be blown by the wind as it tumbles toward the ground.
Such as a system works by being about 30 times as heavy as a 1 milligram dandelion seed. This weight has been configured to contain the necessary monitoring equipment and still be able to travel up to 100 meters in a moderate breeze (about the length of a football field).
Drones can be utilized to release the devices. Once on the ground, the device (holding at least four sensors) is able to call upon solar panels to power an onboard electronics system. In terms of range, the sensors can share sensor data up to 60 meters away.
Describing the technology, Shyam Gollakota, (University of Washington professor in the Paul G. Allen School of Computer Science & Engineering) outlines why the technology adds value to agritech: “Our prototype suggests that you could use a drone to release thousands of these devices in a single drop. They’ll all be carried by the wind a little differently, and basically you can create a 1,000-device network with this one drop…This is amazing and transformational for the field of deploying sensors, because right now it could take months to manually deploy this many sensors.”
The amin challenge with the technology involved the steps necessary to develop a shape that would allow the system to take its time falling to the ground so that it could be tossed around by a breeze.
To achieve this, 75 designs needed to be tested in order to determine which design would lead to the smallest “terminal velocity” (the maximum speed a device would have as it fell through the air). Here, dandelion seed structures became the point of inspiration.
To keep things light, the scientists added solar panels in place of a heavy battery to power the electronics. The devices landed with the solar panels facing upright 95 percent of the time. The shape and structure enabled the contraptions to flip over and fall in a consistently upright orientation similar to a dandelion seed.
To boost power, the researchers designed the electronics to include a capacitor, a device that can store some charge overnight.
For data gathering, the devices use the backscatter method. This involves sending information by reflecting transmitted signals, to wirelessly send sensor data back to the researchers.
With the types of information, the devices measure temperature, humidity, pressure and light. This represents key information to assess environmental change.
The development appears in the journal Nature, titled “Wind dispersal of battery-free wireless devices.”
