Hey look it's a 💥

extremely low-frequency (ELF) magnetic field thrown off by its spinning brushless motors.

Now, researchers at Florida International University (FIU) have figured out how to use ELF to spot incoming threat drones

Typical active radar, optical, and acoustic systems face constraints from line-of-sight barriers, environmental background noise, and strict transmission regulations. Passive ELF magnetic sensing reduces these vulnerabilities by covertly capturing motor emissions. This technique operates silently, without broadcasting signals. It offers a stealthy detection alternative unaffected by weather conditions or acoustic interference.

“While the range of our method is limited for now, it costs only a few hundred dollars to develop and could run continuously without any specialized support, unlike radar systems,” Madanayake said.

The FIU team converts a basic physical requirement of drone flight into an effective security trap.

Although a 49 feet detection range remains modest, the system excels in its stealth and low manufacturing cost. A purely passive receiver emits no signals, making it invisible to hostile forces trying to jam or locate defensive sensors. Electromagnetic fields pass through fog, total darkness, and heavy environmental noise, providing reliable detection where optical and acoustic sensors routinely fail.

IDK, It sounds pretty impressive to me

It's impressive because it's totally passive - radar can locate incoming drones, but also lets the drones locate the radar antenna. This new technique finds the drones without emitting any kind of telltale signal. So the drones don't know they've been spotted, or even that anyone's looking.

So you could hook this system up to a vehicle, like a tank or a troop carrier, and integrate it with a turret, and now you have drone protection. Just look at the havoc Ukrainian drone wrecked on Russian tanks and you'll see why this could be a big deal.

Blind and deaf scientists develop amazing new way to “touch” a drone from 50 feet away using vibrations travelling through the air. “It’s like we’re sensing it from a distance”.

New technique could potentially be developed further to allow people to communicate beyond their reach, potentially even from different (neighbouring) rooms in a house!