When Chad Johnson and his son embarked on their journey to create the Grain Weevil in 2021, they had no formal background in agriculture or robotics. What began as a challenge from a local farmer has now grown into a mission to revolutionize grain bin safety. “A local farmer and a friend of ours saw a robot that my son had made for a completely different purpose, and he challenged my son. He said, ‘If you can build that thing, build one to keep me out of a grain bin,’” Johnson recalls.
Farmers often have to enter grain bins to break up clumps of grain and address other issues. This task is not only labor-intensive and hot but also perilous. The dangers of grain bins are so significant that they inspired the thriller-drama film “Silo,” which depicts a teenager trapped in a grain silo. Grain entrapment incidents claim around two dozen lives annually in the U.S., with the grain acting like quicksand, burying a person in seconds and causing suffocation. The risks are compounded by the need to address spoiled grain, which can form dangerous clumps and bridges.
The Grain Weevil robot, which Johnson and his son displayed at a local Omaha corn growers association event, aims to mitigate these risks. The robot garnered significant attention, with Johnson noting, “One viral video later and it became evident that this was going to be a bigger project than just a fun little thing for my son to do.” The mission, he says, is clear: “no boots in the grain.” By achieving this, Johnson believes they can significantly improve farmer wellbeing.
The statistics are sobering. One in five people who die in grain bins each year is under the age of 20. These younger, more energetic individuals often end up facing the brunt of the dangers. Besides suffocation, other risks include falling from the bin or losing a limb to an auger. Additionally, around 8-10% of U.S. farmers suffer from farmer’s lung, a disease caused by inhaling grain dust.
The Grain Weevil robot is designed to replicate the tasks a human would perform with a shovel, such as breaking up grain crusts, leveling the grain, and spreading out materials that cause problems in grain bins. Johnson explains, “We can make storing grain much more efficient to have the biggest impact on the farmer. Wellbeing is the freedom of not ever being in [the grain bin].” Once the day’s loading is complete, the robot is placed in the bin to inspect and break up any clumps, ensuring no crusts form and moving sidewalls down into the center sump.
The first version of the Grain Weevil, dubbed “the workhorse,” can manage roughly 500,000 bushels of grain per bin and is operated by a human with a remote controller and camera system. While this version has some autonomous capabilities, a forthcoming model will be fully autonomous. Johnson emphasizes the importance of the robot being an efficient tool, noting that their biggest competitor is “the strong-willed farmer with a shovel” who doesn’t believe an accident will happen to them. “Our robot really has to make a return on the investment. That’s been a big focus of ours: making sure that the work the robot does is valuable.”
Grain Weevil’s journey began with participation in the Combine program, an incubator based in Lincoln, Nebraska. Winning the Lemelson MIT student innovation prize during Johnson’s son’s senior year of university brought significant publicity. This May, the company raised a $3.5 million seed round from Homegrown Capital. Starting this fall, Grain Weevil will partner with Midwest U.S. farmers to provide the robots as a service, with a commercial launch targeted for the second quarter of 2025. The company is also conducting trials at commercial grain facilities, which present similar but more demanding challenges. For now, Grain Weevil’s focus remains on the Midwest before expanding to other regions and crops.