Nellie is a 3D-printed weed-picking robot

This Arduino-powered bot may one day help farmers stay weed-free. 

Other than shoveling several inches of snow, there’s one outdoor chore that anyone would surely welcome robotic assistance: weeding. While there are already a number of plowing bots out in existence today, thanks to one Maker, the daunting lawn care task may soon be taken care of as well.


A recent entry in MAKE: Magazine and Cornell University’s Pitch Your Prototype competition, Maker Mike Rigsby has developed a 3D-printed robot capable of, you guessed it, pulling out weeds! While at first this may sound like yet another mechanism to increase laziness, weeds are actually a serious problem for farmers all around the world — and it’s only getting worse. Take for instance Pigweed, which grows up to three inches per day and has become resistant to the dominant weed killers, threatening the nation’s soybean and corn crops.

“This is a serious attempt to address an agricultural problem,” Rigsby told the magazine. “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.”

And so Nellie was born. The robot spots and plucks them the old-fashioned way, one at a time. The current proof-of-concept is powered by a trio of Arduino Unos (ATmega328), a pair of Arduino motor shields, a Pixy camera, a Ping ultrasonic sensor, eleven AA NiMh batteries, a servo motor, a four-wheel drive base, along with some custom 3D-printed parts that were constructed using two AVR powered MakerBot Replicator 2.


How it works is relatively simple. The Pixy camera spots a weed, then feeds the data over to the Arduino processors which relay the commands to the motor controller module to activate the grabber and close the pincer. Meanwhile, the Arduino-controlled motor shield enables the robot to move about the land in the right direction. At the moment, the device is only designed to roll over carpet.

Should the Maker win the contest’s grand prize, however, Rigsby hopes to use the winnings to devise another working prototype with a little more oomph, which can navigate a farm’s terrain. And who knows, perhaps in the coming months, everyday gardeners will be able to take advantage of Nellie, too.


“To advance the project requires money for parts. 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. 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,” Rigsby adds.

Until then, you can watch it in action below. Now this would make for a great Hackay Prize entry as well. Just sayin’.

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