Lasers fry roaches on the fly

Roaches are notoriously hard to eradicate. Their ability to endure has made them emblematic of the last vestige of life that will survive an apocalyptic nuclear exchange. Humans, who like to be upstaged by insects even less than they enjoy finding them in the pantry, can therefore be excused for taking roach eradication to irrational and even dangerous extremes.

Our species, for example, has long relied on broad-spectrum chemical pesticides that leach into the environment where they can linger for decades and cause unintended harm to pollinators, arachnids, and other beneficial insects — not to mention to ourselves. Meanwhile, roaches not only infuriatingly endure these chemicals, they develop a resistance to them.

Courtesy of Courtesy of iStock.com/azerberber.

The point is that humans have demonstrated that personal safety is a secondary consideration to ridding the world of even a few roaches. So, it was only a matter of time before laser-based kill turrets seemed to us like a plausible solution.

This was the approach explored by a team of researchers from Heriot-Watt University and the University of Sussex, who leveraged two cameras, a galvanometer, machine learning, and various laser sources to assemble a system that could dazzle, stun, or outright kill roaches in the lab. The team described the design of its system and its experimental results in the journal Oriental Insects.

A pause here to emphasize that Photonics Media in no way endorses the use of lasers without having rigorous safety practices and protocols in place. And to be fair to the researchers, they clearly note in their paper the inherent risks lasers pose for eye safety and/or fire ignition when employed outside of such controlled settings, such as in the kitchen at home.

In that context, the experimental setup the researchers describe in their article is notable not only for its elegance and simplicity, but also for the safety it ensured to everyone involved … except, of course, to the roaches.

The researchers’ laser-guidance system leveraged a Jetson Nano, which is a single-board computer capable of running deep learning algorithms. They trained the AI using a thousand manually labeled images taken of cockroaches placed in a test box. This training allowed the system’s two 8-MP cameras to quickly identify a roach and pinpoint its location in a three-dimensional space. The data then informed the system’s galvanometer how to adjust its mirrors to steer the laser beam onto the target.

The experiment sampled three lasers of varying wavelengths — 450, 660, and 808 nm — with respective output powers of 300, 100, and 1600 mW. The laser spot sizes and the distances to the target were also varied. The research team found that the lower-power lasers led cockroaches to change direction, accelerate away from the beam, or be deterred from aggregating in a darkened shelter. The most powerful laser, they found, could fully “neutralize” roaches while they were on the move.

Each of the system’s components costs less than $250, which makes the approach a plausible, affordable, and arguably more spectacular alternative to chemical eradication methods. But the inherent danger posed to people, pets, and home insurance rates will likely keep the laser-based method off the market for the foreseeable future.