Drone On Drone Warfare, With Jammers

After the alleged drone attacks on London Gatwick airport in 2018 we’ve been on the look out for effective countermeasures against these rogue drone operators. An interesting solution has been created by [Ogün Levent] in Turkey and is briefly documented on in his Dronesense page on Crowdsupply. There’s a few gaps in the write up due to non-disclosure agreements, but we might well be able to make some good guesses as to the missing content.

Not one, but two LimeSDRs are sent off into the air onboard a custom made drone to track down other drones and knock them out by jamming their signals, which is generally much safer than trying to fire air to air guided missiles at them!

The drone hardware used by [Ogün Levent] and his team is a custom-made S600 frame with T-Motor U3 motors and a 40 A speed controller, with a takeoff weight of 5 kg. An Adventech single board computer is the master controller with a Pixhawk secondary and, most importantly, a honking great big 4 W, 2.4 GHz frequency jammer with a range of 1200 meters.

The big advantage of sending out a hunter drone with countermeasures rather than trying to do it on the ground is that, being closer to the drone, the power of the jammer can be reduced, thus creating less disturbance to other RF devices in the area – the rogue drone is specifically targeted.

One of the LimeSDRs runs a GNU radio flowgraph with a specially designed block for detecting the rogue drone’s frequency modulation signature with what seems to be a machine learning classification script. The other LimeSDR runs another *secret* flowgraph and a custom script running on the SBC combines the two flowgraphs together.

So now it’s the fun part, what does the second LimeSDR do? Some of the more obvious problems with the overall concept is that the drone will jam itself and the rogue drone might already have anti-jamming capabilities installed, in which case it will just return to home. Maybe the second SDR is there to track the drone as it returns home and thereby catch the human operator? Answers/suggestions in the comments below! Video after the break. Continue reading “Drone On Drone Warfare, With Jammers”

Designing Compact Gasoline Generator Prototype For Drone Use

Lithium batteries and brushless motors helped make multirotor drones possible, but batteries only last so long. Liquid fuels have far greater energy densities, but have not  been widely applied in these roles. [Tech Ingredients] has been experimenting with a compact gasoline-fueled generator, with the aim to extend drone flight times well beyond what is currently possible with batteries (Youtube link, embedded below).

The build began with a single-cylinder, four stroke engine. However, torque spikes and vibration made things difficult. After some iteration, the design settled on employing two single-cylinder two stroke engines, fitted with a timing belt to keep them 180 degrees out of phase. In combination with a pair of balanced flywheels, this keeps vibration to a minimum. Brushless motors are used as generators, combined with rectifier diodes and capacitors to smooth the voltage output. The generator is intended to be used in parallel with a lithium battery pack in order to ensure the drone always has power available, even in the event of a temporary malfunction.

This is a build with plenty of promise, and we can’t wait to see what kind of flight time can be achieved once the system is finished and flight ready. We’ve seen others experimenting with hybrid drones, too.

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Hybrid Drones Could Have Massively Extended Flight Times

Multirotor drones truly took off with the availability of lithium polymer batteries, brushless motors, and cheap IMUs. Their performance continues to improve, but their flight time remains relatively short due to the limits of battery technology. [Nicolai Valenti] aims to solve the problem by developing a hybrid generator for drones.

The basic concept consists of a small gasoline engine, connected to a brushless motor employed as a generator. The electricity generated is used to run the main flight motors of the multirotor drone. The high energy density of gasoline helps to offset the added weight of the generator set, and [Nicolai] is aiming to reach a goal of two hours of flight time.

There are many engineering problems to overcome. Engine starting, vibration and rectification are all significant challenges, but [Nicolai] is tackling them and has already commenced flight testing. Experiments are ongoing with 500 W, 1,000 W, and 2,000 W designs, and work is ongoing to optimise the engine and electronics package.

It’s a project that holds the potential to massively expand the range of operation for medium to large multirotors, and should unlock certain capabilities that have thus far been limited by short battery runtimes. Gasoline powered drones aren’t a new idea, but we’ve seen precious little in the hybrid space. We look forward to seeiing how this technology develops. Video after the break.

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DJI Fights Back Over Sensationalist Drone Reporting

Over the past few years the number of reported near misses between multirotors, or drones as they are popularly referred to, and aircraft has been on the rise. While evidence to back up these reports has been absent time and again.

We’ve looked at incident reports, airport closures, and media reporting. The latest chapter comes in the form of a BBC documentary, “Britain’s Next Air Disaster? Drones” whose angle proved too sensational and one-sided for the drone manufacturing giant DJI. They have penned an acerbic open letter to the broadcaster (PDF link to the letter itself) that says that they will be launching an official complaint over the programme’s content. The letter begins with the following stinging critique:

As the world’s leader in civilian drones and aerial imaging technology, we feel it is our duty on behalf of the millions of responsible drone users around the globe, to express our deep disappointment at the BBC’s negative portrayal of drone technology and one-sided reporting based on hearsay.

It then goes on to attack the tone adopted by the presenter in more detail : “overwhelmingly negative, with the presenter frequently using the words ‘catastrophic’ and ‘terrifying’.“, before attacking the validity of a series of featured impact tests and highlighting the questionable basis for air proximity incident reports. They round the document off with a run through the safety features that they and other manufacturers are incorporating into their products.

DJI have pulled no punches in their condemnation of the standard of reporting on drone incidents in this document, and it is a welcome and rare sight in an arena in which the voices of people who know something of multirotors have been rather lonely and ignored. The BBC in turn have responded by saying “its investigation had shown positive uses of drones and that its programmes were fair“.

Over the past few years we have reported on this issue we have continually made the plea for a higher quality of reporting on drone stories. While Britain has been the center of reporting that skews negatively on the hobby, the topic is relevant wherever in the world there are nervous airspace regulators with an eye to any perceived menace. These incidents have pushed the industry to develop additional safety standards, as DJI mentions in their letter: “the drone industry itself has implemented various features to mitigate the risks described”. Let’s hope this first glimmer of a fight-back from an industry heavyweight (with more clout than the multirotor community) will bear the fruit of increased awareness from media, officials, and the general public.

If you’d like to see the BBC documentary in question it will be available for the next few weeks to people who see the Internet through a British IP address.

Thanks [Stuart] for the tip!

Build Your Own Selfie Drone With Computer Vision

In late 2013 and early 2014, in the heady days of the drone revolution, there was one killer app — the selfie drone. Selfie sticks themselves had already become a joke, but a selfie drone injected a breath of fresh air into the world of tech. Fidget spinners had yet to be invented, so this is really all we had. It wasn’t quite time for the age of the selfie drone, though, and the Lily camera drone — in spite of $40 Million in preorders — became the subject of lawsuits, and not fines from the FAA.

Technology marches ever forward, and now you can build your own selfie drone. That’s exactly what [geaxgx] did, although this build uses a an off-the-shelf drone with custom software instead of building everything from scratch.

For hardware, this is a Ryze Tello, a small, $100 quadcopter with a front-facing camera. With the right libraries, you can stream images to a computer and send flight commands back to the drone. Yes, all the processing for the selfie drone happens on a non-flying computer, because computer vision takes processing power and battery life.

The software comes from CMU’s OpenPose library, a real-time solution for detecting a body, face, or hands. With this, [geaxgx] was able to hover the drone and keep his face in the middle of the camera’s frame. While there’s no movement of the drone involved — the drone is just hovering and rotating to the left and right — it is a flying selfie stick without the stick. You can check out the video below and check out all the code on [geaxgx]’s GitHub here.

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Automate The Freight: Autonomous Delivery Hits The Mainstream

It should come as no surprise that we here at Hackaday are big boosters of autonomous systems like self-driving vehicles. That’s not to say we’re without a healthy degree of skepticism, and indeed, the whole point of the “Automate the Freight” series is that economic forces will create powerful incentives for companies to build out automated delivery systems before they can afford to capitalize on demand for self-driving passenger vehicles. There’s a path to the glorious day when you can (safely) nap on the way to work, but that path will be paved by shipping and logistics companies with far deeper pockets than the average commuter.

So it was with some interest that we saw a flurry of announcements in the popular press recently regarding automated deliveries. Each by itself wouldn’t be worthy of much attention; companies are always maneuvering to be seen as ahead of the curve on coming trends, and often show off glitzy, over-produced videos and well-crafted press releases as a low-effort way to position themselves as well as to test markets. But seeing three announcements at one time was unusual, and may point to a general feeling by manufacturers that automated deliveries are just around the corner. Plus, each story highlighted advancements in areas specifically covered by “Automate the Freight” articles, so it seemed like a perfect time to review them and perhaps toot our own horn a bit.

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Well-Built Sentry Gun Addresses The Menace Of Indoor Micro-UAVs

What is this world coming to when you can’t even enjoy sitting in your living room without some jamoke flying a drone in through the window? Is nothing sacred? Won’t someone think of the children?

Apparently [Drew Pilcher] did, and the result is this anti-drone sentry gun.  It’s a sturdily built machine – one might even say it’s overbuilt. The gimbal is made from machined steel pieces, and the swivels are a pair of Sherline stepper-controlled rotary tables with 1/40 of a degree accuracy selling for $400 each. Riding atop that is a Nerf rifle, which is cocked by a stepper-actuated linear slide, as well as a Kinect for object tracking. The tracking app is a little rough – just OpenCV hacked onto the Kinect SDK – but good enough for testing. The gun tracks as smoothly as one would expect given the expensive hardware, and the auto-cocking feature works well if a bit slowly. Based as it is on Nerf technology, this sentry is only indicated for the control of the micro-drones seen in the snuff video below, but really, anyone afflicted by indoor infestations of Phantoms or Mavics has bigger problems to worry about.

Over-engineered? Perhaps, but it’s better than letting the menace of indoor drones go unanswered. And it’s far from the first sentry gun we’ve seen, targeting everything from cats to squirrels using lasers, paintballs, and even plain water.

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