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Associate Professor Gregory Whiting and Research Associate Nikolaus Setiawan discuss electrical measurements. Photo credit: Cameron Douglas

Aerospace engineering undergraduate student Charlotte Bellerjeau working in the Whiting Lab

Farmers struggle to track, shape and understand the composition their soil in real-time.

They know how much fertilizer they spread, or how much water they used, but they don’t necessarily know how those inputs change over time and space. That information just isn’t available with current technology. But what if they had a sensor that was small enough to be out of the way and cheap enough to be tilled under when the season changed? What if that sensor was one of hundreds spread across a field, uploading information to the cloud for exact daily – even hourly – actionable updates on soil conditions? What if the sensor was inside the plant itself?

That kind of interdisciplinary technology could solve massive problems related to food supply and energy conservation. Work at the College of Engineering and Applied Science could make it a reality through several new projects from the USDA and National Science Foundation.

It all starts with faculty and students in the Multifunctional Materials Interdisciplinary Research Theme who came together last year through seed funding to explore issues and share ideas related to printable electronics – a growing strength in the college and research interest across campus. 

Printed electronics is a broad term for various methods of mass-producing electronics, from 3D to inkjet printing. When low cost, distributed systems are needed these printing methods present an advantage over traditional methods in computer chip manufacturing, for example, where cleanrooms and trained workers are needed, upping costs and production time. They also allow for flexibility and customization, both of which are key reasons why such approaches are becoming important in the fields of medicine and communication. 

Using these relatively new methods, devices such as sensors can be manufactured quickly and cheaply and linked together easily, ushering in an era of connectivity today known as the internet of things. Researchers in the Multifunctional Materials Interdisciplinary Research Theme, however, are taking that idea in a new direction with what they call the internet of living things.

Think of the smart thermostat in your house. It can talk to other devices through the Wi-Fi and react in real time to your commands no matter where you are. Now think about having that ability housed in a plant. You could get detailed soil readings based on what it is pulling from the ground or have the plants release a chemical in unison across the field to protect from incoming predators. 

Associate Professor Gregory Whiting is leading the work at CU Boulder. He said that print processing allows his team to make electronics that fit in with the natural environment and a variety of demands. Fertilizer or water use, he said, is a perfect example of the ideas at play.

“If you build sensors in the conventional way to address these needs, you would likely have thousands of devices spread out over a field that would likely be very expensive, require significant maintenance and would potentially create a lot of electronic waste” he said. “By using printed sensors based on materials and structures that can be readily integrated into the soils or plants, you get a more appropriate solution in equilibrium with the surrounding environment. It would not have been possible to get to this point without building from the work in Robert McLeod’s lab developing organic electronics that could be used for sensing in human tissue.”

McLeod, a professor in the Department of Electrical, Computer and Energy Engineering, gave credit for the idea and application to Whiting and the connections forged in the interdisciplinary theme. He said he had never gone from great idea to significant funding so fast, noting that it was more than just having coffee with potential collaborators.

“The theme let us address these calls from a systems wide level, which is rare in proposals. It also let us chew on this idea and get feedback from a lot of people to really refine it before getting a little seed funding,” he said. “It is also rare for a materials guy like myself to be involved in the other end of the process, or to work with computer science researchers on problems like getting the data off the sensors. That kind of early collaboration helps the idea become really strong.”

Environmental Studies Program Professor Jason Neff is working with McLeod and Whiting in this area through an award related to the development of new sensors to monitor soil degradation. 

“The combination of cutting-edge approaches in engineering and material science and campus wide capabilities in the environmental sciences is something that is really unique to CU Boulder" said Neff, who is the director of the Sustainability Innovation Lab at Colorado.    

McLeod said the applications of this work could go beyond agriculture. It could be applied in natural ecosystems or places where humans have had an impact as well.