The KrakenSDR in its metal case, with five small antennas connected to it

Open-Source Passive Radar Taken Down For Regulatory Reasons

Open-source technology brings a world that laws and regulations are not quite prepared for. As a result, every now and then, open projects need to work around governmental regulations. In today’s news, KrakenRF team has stumbled into an arms-trafficing legal roadblock for their KrakenSDR-based passive radar code, and is currently figuring it out. There’s no indication that there’s been any legal action from the USA government – the team’s being proactive, as fas as we’re told.

KrakenSDR hardware, to simplify it a lot, is five RTL-SDRs on one PCB – with plenty of work put in to do it the right way. It gets you much further than a few dongles – there’s shielded case, suitable connectors, reliable power distribution, a proper USB hub, and importantly, receiver synchronization hardware. Naturally, there’s nice things you can build with such a hefty package – one of them is passive radar, which was a prominent selling point on both KrakenSDR’s pre-launch page back in 2021, and on their crowdfunding page just a week ago. How does that work?

There’s RF emissions floating around you in the air, unless you’re at sea or in the desert. Whether it’s airplane transponders, cell towers, or a crappy switch-mode PSU, the radiowaves emitted interact with objects all around you. If you have multiple receivers with directional antennas, you can catch waves being reflected from some object, compare the wave reflected wave to the wave received from the initial source, and determine the object’s properties like location and speed. If you’d like to know more, IEEE Spectrum has covered this topic just a week ago, and the previously-deleted KrakenSDR wiki page has more details for you to learn from.

Through exposure in IEEE Spectrum, the KrakenSDR work has received plenty of attention and comments. And this is where the International Traffic in Arms Regulations (ITAR) laws come in. We’re not lawyers, but it does look like passive radar is on the list. Today, the code repository and the documentation pages are scrubbed clean while the team is talking to legal experts.

Dealing with this is intimidating, and we wish them luck in clearing this with legal. In the bad old days, certain encryption algorithms were famously in scope, which appeared absolutely ridiculous to us at the time. The laws did eventually change to better reflect reality, but the wheels of justice turn slowly.

DefCAD Triggers HTTP 451

Depending on where you live, pointing your browser to yesterday may have shown you something you’d never seen before. It certainly did for me. That’s because I live in one of the two states (as of this writing) in the United States which have scrambled to block access to the online repository of firearm CAD files after they were approved for release by the US State Department.

Anyone using the internet in those states was presented with HTTP status code 451: “Unavailable For Legal Reasons”. This code was named for Ray Bradbury’s dystopian novel “Fahrenheit 451″, in which books are burned to censor the information they contain. Rather than simply returning the traditional 403 error, 451 can be used to signal that the server is willing to serve the user the information, but is being prevented from doing so by court order.

Whatever your personal feelings are on the public having unfettered access to technical information on firearms, this is still a worrying development. The First Amendment covers more than literal speech: source code and technical data is a form of expression just as much as a poem or song, and are equally protected. If the federal government believes the files that Cody Wilson’s Defense Distributed offers up are not restricted by International Traffic in Arms Regulations (ITAR), then how can a citizen of the United States not view them? The question remains unanswered and overnight a federal judge granted a restraining order to restrict the website for the remaining states.

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3D Printed Gun Saga: Court Case Over CAD Files Settled

Can you create 3D printed designs and distribute them freely and without restriction? Maybe, and it’s likely to become easier in the future. A settlement has been reached in the saga of the US Department of State versus Cody Wilson, and beginning August 1st the Defense Distributed library of gun designs will once again become available.

Cody is well known for creating the first 3D printed gun. He went on to found Defense Distributed, a company that published designs and technical files for 3D printing firearms before being pulled into litigation that sought to curb the distribution of such plans by subjecting them to International Traffic in Arms Regulations (ITAR) restrictions. Read that carefully, it’s the (international) distribution of CAD files at question here, and not the act of 3D printing, and Defense Distributed has been granted an ITAR exemption. Will other arms-related design files be similarly exempted? The settlement mentions upcoming rule changes seeking to make this type of exemption the standard.

As members of the Hackaday community, we’re the people to whom our friends and family turn for perspective when new technology makes it into their news feeds. Those with little or no exposure to 3D printing may easily fall to doom and gloom reports. But is this a story of doom and gloom? Absolutely not, guns are still guns and 3D printers are still 3D printers. Let’s take a look.

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Would You Look At That Yaw Control

[Jeff Bezos] might be getting all the credit for developing a rocket that can take off and land vertically, but [Joe Barnard] is doing it the hard way. He’s doing it with Estes motors you can pick up in any hobby shop. He’s doing it with a model of a Falcon 9, and he’s on his way to launching and landing a rocket using nothing but solid propellant.

The key to these launches is, of course, the flight controller, This is the Signal flight controller, and it has everything you would expect from a small board meant to mount in the frame of a model rocket. There’s a barometer, an IMU, a buzzer (important!), Bluetooth connectivity, and a microSD card slot for data logging. What makes this flight computer different is the addition of two connectors for standard hobby servos. With the addition of a 3D printed adapter, this flight controller adds thrust vectoring control. That means a rocket will go straight up without the use of fins.

We’ve seen [Joe]’s work before, and things have improved significantly in the last year and a half. The latest update from last weekend was a scale model (1/48) of the Falcon Heavy. In a 45-second video, [Joe]’s model of the Falcon Heavy launches on the two booster rockets, lights the center core, drops the two boosters and continues on until the parachutes unfurl. This would be impressive without active guidance of the motor, and [Joe] is adding servos and launch computers to the mix. It’s awesome, and certainly unable to be exported from the US.

Building Homebrew VTOL Rockets

No one can deny what SpaceX and Blue Origin are doing is a feat of technological wizardry. Building a rocket that takes off vertically, goes into space, and lands back on the pad is an astonishing technical achievement that is literally rocket science. However, both SpaceX and Blue Origin have a few things going for them. They have money, first of all. They’re building big rockets, so there’s a nice mass to thrust cube law efficiency bump. They’re using liquid fueled engines that can be throttled.

[Joe Barnard] isn’t working with the same constraints SpaceX and Blue Origin have. He’s still building a rocket that can take off and land vertically, but he’s doing it the hard way. He’s building VTOL model rockets. Most of the parts are 3D printed. And he’s using solid motors you can buy at a hobby shop. This is the hard way of doing things, and [Joe] is seeing some limited success with his designs.

While the rockets coming out of Barnard Propulsion Systems look like models of SpaceX’s test vehicles, there’s a lot more here than looks. [Joe] is using a thrust vectoring system — basically mounting the Estes motor in a gimbal attached to a pair of servos. This allows the rockets to fly straight up without fins or even the launch rod used to get the rocket up to speed in the first few millseconds of flight. This is active stabilization of a model rocket, with the inevitable comments of ITAR violations following soon afterward.

Taking off vertically is one thing, but [Joe] is also trying to land his rockets vertically. Each rocket he’s built has a second Estes motor used only for landing. During descent, the onboard microcontroller calculates the speed, altitude, and determines if it’s safe to attempt a vertical landing. If the second motor has sufficient impulse to make velocity and altitude equal zero at the same time, the landing legs deploy and the rocket hopefully makes a soft touchdown in the grass.

While [Joe] hasn’t quite managed to pull off a vertical takeoff and landing with black powder motors quite yet, he’s documenting and livestreaming all of his attempts. You can check out the latest one from a week ago below.

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Do Your Projects Violate International Traffic In Arms Regulations?

From time to time we consider the ramifications of hacking prowess being used for evil purposes. Knowledge is a powerful thing, but alone it is not a dangerous thing. Malicious intent is what takes a clever project and turns it to a tragic end. Conscientious hackers realize this, and [George Hadley] is one of them. While working on a new project he wondered if there were guidelines as to what knowledge should and should not be shared. It turns out that the United States has a set of International Traffic in Arms Regulations that mention concepts we’ve seen in many projects. He wrote up an article which covers the major points of the ITAR.

The gist of it is that sharing certain knowledge, by posting it on the Internet or otherwise, can be considered arms trafficking. It’ll get you a not-so-friendly visit from government officials and quite possibly a sponsored stay in a secure facility. Information about DIY radar, communications jamming, spying devices, UAVs, and a few other concepts are prohibited from being shared. The one qualifying part of that restriction is that it only applies if the information is not publicly known.