Engineers' Day: How Young Innovators Turned An Idea Into India's First Affordable Laser Weeder To Help Farmers

Weeds are one of the biggest challenges that farmers face, as they can lower crop production and increase expenses. Traditional approaches to managing weeds involve either manual labour or chemical herbicides, but both have their downsides. Manual weeding is expensive and time consuming, making up nearly a quarter of farming costs. On the other hand, chemical weedicides, though effective initially, can harm human health and the environment in the long term.

In India, the annual loss caused by weeds in ten major crops is estimated to be over ₹90,000 crore, or about $11 billion, according to the ICAR-Directorate of Weed Research (ICAR-DWR) in Jabalpur.

To address the issue, a group of final-year engineering students at Mahindra University in Hyderabad came up with a creative solution. The team, led by Rahul Arepaka, created an AI-powered laser weeder designed to be a sustainable and chemical-free alternative for farmers. Their invention, named Rakshak, uses precision laser technology and artificial intelligence to detect and remove weeds without damaging crops or disturbing the soil.

AI-Tech Solution to an Agricultural Problem

The idea for Rakshak took shape in late 2022, when Rahul and his teammates, from different engineering disciplines, explored ways to automate weed control without using chemicals or costly manual labour. They had experience working with agricultural robotics through competitions like the World Robotics Olympiad. During an internship with Farmbot, Rahul worked on a laser weeding prototype and saw how there was a big gap in the Indian market.

The team received an initial funding of ₹5 lakh from Mahindra University's start-up incubation centre and began building their first prototype in mid-2023. Over the next eight months, they raised an additional ₹18 lakh in investment to improve the hardware and software components.

What sets Rakshak apart from similar global solutions is its cost-effective yet powerful laser system. Rahul shared with The Better India that their system uses five lower-powered lasers together to produce the necessary 200-watt output for effective weed removal in Indian soil conditions.

Most laser weeders abroad use a single high-powered laser, typically around 1,200 watts, which alone can cost more than $40,000. And that kind of price simply does not work in the Indian context.

By distributing the power across five separate laser sources, the team has greatly reduced both cost and maintenance.

How Rakshak Operates

The system Rakshak is mounted on a standard tractor using a three-point linkage system. It is powered entirely through the tractor's battery, either via the PTO (power take-off) system or a trailer socket, and does not require an external power source. The device is equipped with advanced computer vision and deep learning algorithms that help in identifying weeds and crops in real time.

The cameras in the system capture images of the ground as the tractor moves through the field, and the AI system identifies unwanted plants. Then, precise blue laser beams are directed at the base of the weeds, destroying their internal water cells and killing them at the root. This method keeps the soil structure intact and avoids chemical contamination.

Remarkably, Rakshak requires no additional training for farmers and is compatible with just about any tractor, making it a user-friendly, plug-and-play solution suitable for both small and large farms.

A Homegrown Innovation with Global Reach

Laser-based weeding is not a new concept. However, most existing machines are very expensive. They are also bulky and rely on carbon dioxide-based lasers, which are costly to maintain and difficult to scale. Rahul explains that they have used visible blue laser technology instead of using invisible infrared lasers. This makes the process faster and more effective at removing weeds.

The start-up behind Rakshak, Harvested Robotics, has already tested the device on various farms in India. The company is now part of Microsoft's Startups Founders Hub and is working with Mahindra & Mahindra for large-scale trials.

The team plans to launch the product in the market with an estimated price of ₹10 lakh, which is significantly lower than any comparable solution available worldwide.

Through AI, robotics, and laser technology, these young engineers are not only tackling a major agricultural challenge but also contributing to a greener and more efficient future in farming.

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