Robot born on a Nebraska farm offers hope for better grain bin safety

Grain Weevil recently earned the Innovation Award, with a $50,000 prize, at the 2022 American Farm Bureau Association annual meeting. The creators say it also helps with grain quality and work efficiency on the farm.

Ben Johnson and Zane Zents show the Grain Weevil robot on a pile of grain between two silver bins.
Ben Johnson, left, and Zane Zents, are developing the Grain Weevil robot to work inside grain bins.
Contributed / Cecil Smalley Photography
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AURORA, Neb. — Chad and Ben Johnson can envision a day in the not too distant future when a farmer puts a robot into a bin to level the grain inside.

As the farmer goes about other business on the farm, his phone buzzes with a text message from the robot with a report that tells him how much grain is in the bin and that there are a couple of hot spots, and provides photos to help assess the quality of the grain.

The father and son from Aurora, Nebraska, are working on just such a robot, known as the Grain Weevil, designed to improve grain bin safety, make a farm more efficient and enhance grain quality.

The idea was born out of a request from a farmer neighbor, Zach Hunnicut, who had seen robots that Ben had worked on in high school.

"He said, 'hey, if you can build that robot then you should be able to build me one to keep my family out of the bin,'" Ben said.


Hunnicut said it was a comment made in the heat of the moment, so to speak, after cleaning out a bin on a summer day.

"It was hot, sweaty, dirty job that I didn't want to do," he said.

From there, the idea and the robot have evolved.

The Grain Weevil inside a bin
The Grain Weevil is designed to break through crusted grain, keeping farmers out of grain bins, which are a dirty and dangerous place to work.
Contributed / Cecil Smalley Photography

“It's really neat that it’s gone from just the safety aspect to workflow efficiency,” said Chad, Ben's father.
The initial idea was a robot to just break up crusts and bridges inside the bin.

The Johnsons, who are not farmers and had never been inside a grain bin, said they had no idea what the project would eventually entail.

"We didn’t think of it as a business at first," Ben said. "It was just a fun project to help out a friend."

But then came the realization that this could have a reach far beyond a single farm in Nebraska.

So the Johnson's started Grain Weevil Corp. , with Chad as CEO and Ben as chief innovation officer. The business recently earned the Innovation Award, with a $50,000 prize, at the 2022 American Farm Bureau Federation annual meeting.


Teacher and student

Chad Johnson jokes that both he and Ben have a "double-E" degree.

Chad's EE is in elementary education. While he says he is an "educator at heart," he's also a tinkerer and guy who likes to spend a lot of time in the shop figuring these out."

He also was heavily involved in the robotics club in the Aurora community where Ben got introduced to the technology. Ben graduated in May 2021 from the University of Nebraska Omaha with a degree in electrical engineering.

Hunnicut and his kids also have been involved in the robotics club.

Ben's college roommate, Zane Zents, is now the lead software engineer in the company, which is up to four employees, also including Jeremy Heeg, chief technology officer.

Chad Johnson said they just went through a round of seed money investments, raising $1.6 million, and "quite a few farmers invested in that round."

The Grain Weevil robot
The Grain Weevil can churn up grain, helping aerate the grain and help with leveling and emptying bins.
Contributed / Cecil Smalley Photography

The Grain Weevil team has been putting prototype robots to the test inside grain bins in Nebraska and Tennessee. It's been tested on a variety of stored grain, including corn, soybeans, wheat, dry edible beans and rice. One Nebraska farm put a mix of cover crops, peas and oats, for the Grain Weevil to work on.


"It's not a very good environment. It's dusty, they lock together," which makes it a good challenge as they teach the battery operated robot to operate autonomously, Ben said.

The robot also went through the first harvest season on the neighbor's farm and will get put to work helping to empty bins when it's time to make some sales.

Hunnicut has seen the Grain Weevil at work on crusted grain.

"It just busts right right through it," he said.

He said when seeing it break through a bridge of grain only to right itself, he sometimes thinks "what if that was a person out there," knowing that grain can quickly bury a person working in a bin.

"It takes out the drudgery and the danger," he said.

What's next

Chad Johnson said the prize money earned will go toward achieving safety certifications that are needed before the robot can be sold commercially.

The hope is for commercial sales to start in 2023. The safety certifications are needed to ensure that the robot won't cause an explosion in a bin filled with combustible grain dust.

Chad Johnson said manufacturing will likely stay in Nebraska, where they have been working with manufacturers to supply components of the Grain Weevil, which the team can then assemble.

While first generation of Grain Weevil is in the works, the wheels are already spinning on a next generation of the robots, perhaps with different attachments, capable of more tasks, such as grabbing grain samples and sweeping up an empty bin.

Chad says he tells farmers that "we're ready to replace their shovel but the broom will be next."

Reach Jeff Beach at or call 701-451-5651 (work) or 859-420-1177.
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