Triggering Lightning And Safely Guiding It Using A Drone

Every year lightning strikes cause a lot of damage — with the high-voltage discharges being a major risk to buildings, infrastructure, and the continued existence of squishy bags of mostly salty water. While some ways exist to reduce their impact such as lightning rods, these passive systems can only be deployed in select locations and cannot prevent the build-up of the charge that leads up to the plasma discharge event. But the drone-based system recently tested by Japan’s NTT, the world’s fourth largest telecommunications company, could provide a more proactive solution.

The idea is pretty simple: fly a drone that is protected by a specially designed metal cage close to a thundercloud with a conductive tether leading back to the ground. By providing a very short path to ground, the built-up charge in said cloud will readily discharge into this cage and from there back to the ground.

To test this idea, NTT researchers took commercial drones fitted with such a protective cage and exposed them to artificial lightning. The drones turned out to be fine up to 150 kA which is five times more than natural lightning. Afterwards the full system was tested with a real thunderstorm, during which the drone took a hit and kept flying, although the protective cage partially melted.

Expanding on this experiment, NTT imagines that a system like this could protect cities and sensitive areas, and possibly even use and store the thus captured energy rather than just leading it to ground. While this latter idea would need some seriously effective charging technologies, the idea of proactively discharging thunderclouds is perhaps not so crazy. We would need to see someone run the numbers on the potential effectiveness, of course, but we are all in favor of (safe) lightning experiments like this.

If you’re wondering why channeling lightning away from critical infrastructure is such a big deal, you may want to read up on Apollo 12.

Budget-Minded Synthetic Aperture Radar Takes To The Skies

Unless you work for the government or a large corporation, constrained designs are a fact of life. No matter what you’re building, there’s likely going to be a limit to the time, money, space, or materials you can work with. That’s good news, though, because constrained projects tend to be interesting projects, like this airborne polarimetric synthetic aperture radar.

If none of those terms make much sense to you, don’t worry too much. As [Henrik Forstén] explains, synthetic aperture radar is just a way to make a small radar antenna appear to be much larger, increasing its angular resolution. This is accomplished by moving the antenna across a relatively static target and doing some math to correlate the returned signal with the antenna position. We saw this with his earlier bicycle-mounted SAR.

For this project, [Henrik] shrunk the SAR set down small enough for a low-cost drone to carry. The build log is long and richly detailed and could serve as a design guide for practical radar construction. Component selection was critical, since [Henrik] wanted to use low-cost, easily available parts wherever possible. Still, there are some pretty fancy parts here, with a Zynq 7020 FPGA and a boatload of memory on the digital side of the custom PCB, and a host of specialized parts on the RF side.

The antennas are pretty cool, too; they’re stacked patch antennas made from standard FR4 PCBs, with barn-door feed horns fashioned from copper sheeting and slots positioned 90 to each other to provide switched horizontal and vertical polarization on both the receive and transmit sides. There are also a ton of details about how the radar set is integrated into the flight controller of the drone, as well as an interesting discussion on the autofocusing algorithm used to make up for the less-than-perfect positional accuracy of the system.

The resulting images are remarkably detailed, and almost appear to be visible light images thanks to the obvious shadows cast by large objects like trees and buildings. We’re especially taken by mapping all combinations of transmit and receive polarizations into a single RGB image; the result is ethereal.

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Hackaday Links: February 9, 2025

January 9 ended up being a very expensive day for a Culver City, California man after he pleaded guilty to recklessly operating a drone during the height of the Pacific Palisades wildfire. We covered this story a bit when it happened (second item), which resulted in the drone striking and damaging the leading edge of a Canadian “Super Scooper” plane that was trying to fight the fire. Peter Tripp Akemann, 56, admitted to taking the opportunity to go to the top of a parking garage in Santa Monica and launching his drone to get a better view of the action to the northwest. Unfortunately, the drone got about 2,500 meters away, far beyond visual range and, as it turns out, directly in the path of the planes refilling their tanks by skimming along the waters off Malibu. The agreement between Akemann and federal prosecutors calls for a guilty plea along with full restitution to the government of Quebec, which owns the damaged plane, plus the costs of repair. Akemann needs to write a check for $65,169 plus perform 150 hours of community service related to the relief effort for the fire’s victims. Expensive, yes, but probably better than the year in federal prison such an offense could have earned him.

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Hackaday Links: January 26, 2025

Disappointing news this week for those longing for same-hour Amazon delivery as the retail giant tapped the brakes on its Prime Air drone deliveries. The pause is partially blamed on a December incident at the company’s Pendleton, Oregon test facility, where two MK30 delivery drones collided in midair during light rain conditions. A Bloomberg report states that the crash, which resulted in one of the drones catching fire on the ground, was due to a software error related to the weather. As a result, they decided to ground their entire fleet, which provides 60-minute delivery to test markets in Arizona and Texas, until a software update can be issued.

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DIY Drones Deliver The Goods With Printed Release

It seems like the widespread use of delivery drones by companies like Amazon and Wal-Mart has been perpetually just out of reach. Of course robotics is a tricky field, and producing a fleet of these machines reliable enough to be cost effective has proven to be quite a challenge. But on an individual level, turning any drone into one that can deliver a package is not only doable but is something [Iloke-Alusala] demonstrates with their latest project.

The project aims to be able to turn any drone into a delivery drone, in this case using a FPV drone as the platform. Two hitch-like parts are 3D printed, one which adds an attachment point to the drone and another which attaches to the package, allowing the drone to easily pick up the package and then drop it off quickly. The real key to this build is the control mechanism. [Iloke-Alusala] used an ESP32 to tap into the communications between the receiver and the flight controller. When the ESP32 detects a specific signal has been sent to the flight controller, it can activate the mechanism on the 3D printed hitch to either grab on to a package or release it at a certain point.

While this is a long way from a fully autonomous fleet of delivery drones, it goes a long way into showing that individuals can use existing drones to transport useful amounts of material and also sets up a way for an ESP32 to decode and use a common protocol used in drones, making it easy to expand their capabilities in other ways as well. After all, if we have search and rescue drones we could also have drones that deliver help to those stranded.

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Avian-Inspired Drones: How Studying Birds Of Prey Brings More Efficient Drones Closer

The EPFL LisRaptor with adjustable wings and tail.
The EPFL LisRaptor with adjustable wings and tail.

Throughout evolution, the concept of powered flight has evolved and refined itself multiple times across both dinosaurs (birds), mammals (bats) and insects. So why is it that our human-made flying machines are so unlike them? The field of nature-inspired flying drones is a lively one, but one that is filled with challenges. In a recent video on the Ziroth YouTube channel, [Ryan Inis] takes a look at these efforts, in particular those of EPFL, whose recent RAVEN drone we had a look at recently already.

Along with RAVEN, there is also another project (LisRaptor) based on the Northern Goshawk, a bird of prey seen in both Europe and North-America. While RAVEN mostly focused on the near-vertical take-off that smaller birds are capable of, this project studies the interactions between the bird’s wings and tail, and how these enable rapid changes to the bird’s flight trajectory and velocity, while maintaining efficiency.

The video provides a good overview of this project. Where the LisRaptor differs from the animal is in having a rudder and a propeller, but the former should ideally not be necessary. Obviously the kinematics behind controlled flight are not at all easy, and the researchers spent a lot of time running through configurations aided by machine learning to achieve the ideal – and most efficient – wing and tail configuration. As these prototypes progress, they may one day lead to drones that are hard to differentiate from birds and bats.

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Hackaday Links: January 12, 2025

The big news story of the week of course has been the wildfires in California, which as of Saturday have burned over 30,000 acres, destroyed 12,000 structures, caused 150,000 people to evacuate, and killed eleven people. Actually, calling them wildfires underplays the situation a bit because there are places where they’ve clearly become firestorms, burning intensely enough to create their own winds, consuming everything in their path in a horrific positive feedback loop. We’ve even seen fire tornados caught on video. We’ve got quite a few connections to the affected area, both personally and professionally, not least of which are all our Supplyframe colleagues in Pasadena, who are under immediate threat from the Eaton fire. We don’t know many details yet, but we’ve heard that some have lost homes. We’ve also got friends at the Jet Propulsion Labs, which closed a few days ago to all but emergency personnel. The fire doesn’t seem to have made it down the mountain yet, but it’s very close as of Saturday noon.

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