Amaranthus palmeri, commonly known as pigweed, has long threatened cotton and soybean crops in the southern United States. More recently, it’s begun to develop a resistance to glyphosate, a common agricultural herbicide—posing a problem so grave that farmers in Texas lobbied the EPA last year to let them deploy the severe chemical propazine to fight the weed.

PitchYourPrototype_125x125_v1It was with that situation in mind that Maker Mike Rigsby developed Nellie, a prototype robot that seeks out weeds—proxied in Rigsby’s tests by a printout of his own head, growing on a spindly stalk—and pulls them out of the ground.

“This is a serious attempt to address an agricultural problem,” Rigsby said. “I suspected that robots could handle the weeds and that the time to start working on such a solution is now, before the weeds develop further resistance to chemicals.”

Of course, Rigsby’s tests have taken place on a carpet, not a rugged agricultural field where Nellie would need to deal with grit, inclement weather and gnarly root systems. If he wins, Rigsby says he’ll use his $5,000 in Pitch Your Prototype funds to build a more rugged version of the robot.

The Pitch Your Prototype challenge is a collaboration between Make: and Cornell University with the goal of digging up promising ideas from the Maker community. Visit this page to read the full rules, cast your vote or enter your own project.

“Nellie’s daughters and sons will need a heavy duty chassis that will run between rows of plants, reaching to the side to eliminate offensive weeds,” wrote Rigsby, who has written a number of books on DIY projects, in his entry materials. “They need multiple cameras and better vision to pinpoint the target. Weeds will be eliminated by pulling, burning, cutting, digging, electrocuting or some combination of methods.”

The prototype Nellie is made from three Arduino Unos, two Arduino motor sheilds, a Pixy camera and a Ping ultrasonic sensor, 11 AA NiMh batteries, a Canakit four wheel drive base and a pincer assembly that Rigsby 3D printed.

If future versions show promise, Rigsby says he would build and sell a handful of units to organic farmers before courting more buyers.

“I am also aware of the frustration of farmers regarding high tech, proprietary, expensive, non user repairable equipment,” said Rigsby, who built an electric car while he studied at Vanderbilt University in the 1970s. “I think open source robots would be welcome while closed source devices would have a more difficult time finding acceptance.”


Jon Christian is the co-editor of the Maker Pro Newsletter, which covers the intersection between makers and business. He's also written for the Boston Globe, WIRED and The Atlantic.

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