Affordable Sensors Improve Groundwater Monitoring and Environmental Research
Researchers at Purdue University have developed an affordable alternative to expensive groundwater sensors, making it easier to study how water moves beneath the earth's surface. The innovative device uses 3D printing technology and open-source design principles to improve access to environmental monitoring tools.
The project is led by Jacob Hosen, assistant professor of internet-of-things and ecological analytics in the Department of Forestry and Natural Resources at Purdue University's College of Agriculture.
Working with a team of researchers and engineers, Hosen designed sensors that can measure both the speed and direction of groundwater flow.
The devices contain circuit boards equipped with temperature sensor arrays and are protected by specially designed 3D-printed housings. These housings are created to closely mimic natural soil conditions, helping ensure accurate readings without disturbing water movement.
"A big part of designing an accurate sensor is creating a housing that won't disrupt the water flow," Hosen explained. "We're 3D printing textures that will recreate the soil environment, so the water flows through the sensor in the same way it flows through the ground."
One of the major advantages of the new technology is affordability. The team sources a limited number of components from U.S.-based vendors and completes much of the assembly process in-house using a 3D printer and a modified toaster oven.
"We can make all of this with just a few vendors in the U.S., and then do the rest of the assembly in-house for just a few hundred dollars a unit," Hosen said. "That's not something you can do in most ecology labs."
The project also provides valuable learning opportunities for students. Both undergraduate and graduate students gain practical experience in circuit board assembly, 3D printing, manufacturing, and prototype development.
"It's a useful proof of concept of a different way of building these types of devices," he said.
Durability tests showed that the sensors operated underwater for seven to eight months without failure. The devices can also transmit information wirelessly through LoRa networks while storing data locally as a backup.
"In a university setting, aligning infrastructure with research needs is challenging," Hosen said. "We've done that successfully here, and we should be proud of that."
The sensors will undergo field testing at monitoring locations and could support groundwater tracking, wetland research, contamination studies, infrastructure assessments, and water management projects.
"It works anywhere that water moves underground," Hosen said.