“My son, Ben, built competitive robots all through high school, but he and I had never been in a grain bin before,” said Chad Johnson, a former educator with the Nebraska Public Power District. “We had a lot to learn.”

After months of work, the Johnsons developed the Grain Weevil. This robot directly engages the surface of the grain to help maintain grain quality, while keeping people safe.

“Grain bins can be dirty, dangerous workplaces,” said Johnson, co-founder and CEO of the Grain Weevil Corporation, based in Aurora, Nebraska. “Instead of a farmer needing to enter the bin, which can be dangerous, the Grain Weevil can move through the bin to level the grain, break up crusts and feed grain into extraction augers.”

No boots in the grain

-Submitted photo
The robotic Grain Weevil works to move through the grain bin to level the grain, break up crusts and feed grain into extraction augers. It has a 5- to 6-horsepower electric drive train.

The danger associated with grain bins attracted renewed attention in 2019 and early 2020, thanks to the film “Silo,” which played in movie theaters across the country.

In the film, disaster struck in a small American farm town when a teenage boy became the victim of a grain entrapment. As corn shifted like quicksand inside of a 50-foot silo, the town locals were forced to put aside their deeply rooted differences to save the teenager from drowning in the grain.

“That movie was powerful, especially when you learn that 20% of the people who die in grain bins are teenage boys,” Johnson said.

By early 2020, Johnson and his son had developed a prototype of the Grain Weevil, a robot that looks like a big insect scurrying across the surface of the grain.

The Hamilton County Corn Growers invited the Johnsons to bring their new robot to the 12th Street Cinema in Aurora when “Silo” was showing there.

“Someone took a video of the robot, and it went viral on Twitter with more than 80,000 views,” Johnson said. “People told us a robot like this could make a real difference on farms. That’s what prompted us to keep moving forward with the project.”

The Johnsons reached out to their farmer friends for feedback as they refined their design.

“We approached this project from an outsider’s perspective, since we didn’t have a farm background,” Johnson said. “If we didn’t know something about grain or grain bins, we’d ask the farmers.”

Technological advancements in an industry far removed from agriculture also helped the Johnsons improve the Grain Weevil, which was originally powered with a cordless drill battery.

“The electric scooter industry has developed small, light-weight scooters with powerful motors,” Johnson said. “This technology didn’t exist six years ago, but it’s been key to our project.”

The Grain Weevil, which weighs less than 50 pounds, has a 5- to 6-horsepower electric drive train.

“It was an interesting challenge for us to try to figure out how to propel the robot through the grain,” Johnson said. “The physics of the grain bin itself, from the angles of the bin to the moisture of the grain, influence how the robot works. We tried a few bad designs before we came up with something that worked.”

The Johnsons knew they were on the right track after they designed their own augers for the robot, using a 3-D printer to produce them.

“Then we met Vance Lundell at an ag trade show,” said Johnson, referring to the founder and owner of Odebolt-based Lundell Plastics, which engineers custom plastic products like poly auger flighting and more. “We needed right-handed augers and left-handed augers for each robot, and Lundell Plastics was able to help.”

Set it and forget it

In the last few years, the Grain Weevil business has become a family affair. Johnson’s wife, Alesa, is office manager/bookkeeper. Their son, Ben, 23, who earned his electrical engineering degree from the University of Nebraska-Omaha, is part of the full-time team that includes seven employees.

The company’s engineers keep improving the Grain Weevil, which currently runs on a remote-control system. In a 48-foot-diameter bin with 15% moisture grain, it takes about eight to nine hours for the robot to complete its work.

“It’s not fun driving the robot after a few hours, but it’s still better than going in the bin with a shovel,” Johnson said.

When the Grain Weevil is moving through 15% moisture grain, the battery on the robot lasts about two hours before it needs to be recharged.

“As long as you have electricity at the grain bin site, you can fully charge the battery right there in about 20 minutes,” said Johnson, who added that this specialized battery is safe and won’t catch on fire. “Also, you can have more than one robot working in a grain bin at the same time.”

The Grain Weevil team is also using technology like 3-D mapping (to account for temperature, moisture and grain quality), so the Grain Weevil can operate on autonomous patterns, much like a robotic vacuum cleaner. The autonomous capabilities allow the Grain Weevil robot to have a greater impact than just safety. Grain Weevil utilizes BinAssist technology to help manage grain bins from start to finish.

“If you want to level the grain, for example, you’ll select this option,” said Johnson, whose team is incorporating software that “teaches” the robot how to work most efficiently.

“Then you can go watch a football game while the robot works. When the job is complete, the robot will text you and will shut itself off. Our mission is ‘no boots in the grain.'”

One grain bin accident is too many

Farmers have gotten a glimpse of the Grain Weevil at Landus’ Innovation Connector in Des Moines, as well as the 2023 Iowa Ag Expo in early February in Des Moines.

Ben Johnson is also helping share this technology with a wider audience. “Ben didn’t grow up on a farm, but he talks to young people about high-tech ag careers and explains that there are many opportunities for robotics in agriculture,” Chad Johnson said.

While the Grain Weevil isn’t ready for market just yet, the company plans to start selling the robots after the 2023 harvest.

“Everyone says, ‘It can’t happen to me,’ but one accident in a grain bin is too many,” Johnson said. “We hope the Grain Weevil creates positive changes in how people manage grain bins.”

The Grain Weevil team also stays in touch with the Hunnicutt family and often test their robots on the family’s Nebraska farm.

“Farmers are creative thinkers,” Johnson said. “Zach, his brother Brandon, and his dad, Daryl, give us new ideas for how to use robots on the farm.”