A British company has begun shipping a solar- and battery-powered robot that finds weeds with cameras and kills them with a short pulse of concentrated light instead of herbicide.
Earth Rover, founded in 2017, calls the machine CLAWS, short for Concentrated Light Autonomous Weeding and Scouting. The company has sold its first 10 pilot units, with 15 more being built for delivery over the next quarter, according to AgFunderNews and The Robotics Media.
How it works
The robot drives itself up and down vegetable beds. Cameras and software pick out the weeds, and the machine fires a brief pulse of light at each one.
“It moves up and down the field, identifies weeds, protects the crop, zaps the weed with a small pulse of concentrated light, enough to boil the meristem and kill that weed off,” CEO James Miller told AgFunderNews. The meristem is the growing point of the plant.
Miller said the system does not use a laser beam. “We converge the light, much like a schoolboy would with a magnifying glass making mischief,” he said. Past that focal point the light spreads out, which he said makes it eye-safe beyond a set distance.
Because it uses less power than laser weeders, the robot can run on batteries and solar panels for up to 16 hours.
Cameras front and back also record data on each plant, including position and health.
Why farmers want it
Miller said the idea came from an organic grower. Organic farms can only weed by hand or with machines that must go into the field when the ground is dry, he said, and hand labor is costly and hard to find.
Miller said conventional farmers are now calling, too. Some of the chemicals they relied on are being banned, and some weeds no longer die when sprayed. “It doesn’t really care whether it’s herbicide-resistant or not,” he said of the light pulse. He said the robot works in rain and wind, since ground moisture does not affect it.
Miller said it works to millimeter precision and, in onion fields, can hit a weed growing right next to the emerging crop.
Cost and payback
The price is about £150,000, with a discount for early buyers. Earth Rover sells the robots outright. Miller said the company had considered renting out weeding as a service, but “all farmers want to weed when they want to weed,” so they want to own the equipment.
He said customers have seen payback in one to three years, depending on what they were spending on weeding before. The robot was designed for a 100-hectare vegetable or salad farm, about 250 acres, but Miller said some buyers farm as little as five to 15 hectares.
The chassis adjusts to beds 1.5 to 2 meters wide, and most parts are off the shelf. The company’s chairman is a fifth-generation farmer, and Miller said that shaped the design. “It had to be repairable with baler twine, WD-40, and a hammer!” he said.
Earth Rover has been funded by private investors and British government grants. It plans to raise a larger round next year and move from vegetables into broadacre crops such as grain.
What it means
The price puts CLAWS out of reach for a family garden, and so far only a handful of farms are using it. A machine that runs on sunlight, needs no chemicals and can be fixed with tools found in any farm shop gives growers one more way to cut their dependence on expensive inputs and scarce labor.