Hackaday Links: July 4, 2021

July 4, 2021 by Dan Maloney 9 Comments

With rescue and recovery efforts at the horrific condo collapse in Florida this week still underway, we noted with interest some of the technology being employed on the site. Chief among these was a contribution of the Israeli Defense Force (IDF), whose secretive Unit 9900 unveiled a 3D imaging system to help locate victims trapped in the rubble. The pictures look very much like the 3D “extrusions” that show up on Google Maps when you zoom into a satellite view and change the angle, but they were obviously built up from very recent aerial or satellite photos that show the damage to the building. The idea is to map where parts of the building — and unfortunately, the building’s occupants — ended up in the rubble pile, allowing responders to concentrate their efforts on the areas most likely to hold victims. The technology, which was developed for precision targeting of military targets, has apparently already located several voids in the debris that weren’t obvious to rescue teams. Here’s hoping that the system pays off, and that we get to learn a little about how it works.

Radio enthusiasts, take note: your hobby may just run you afoul of authorities if you’re not careful. That seems to be the case for one Stanislav Stetsenko, a resident of Crimea who was arrested on suspicion of treason this week. Video of the arrest was posted which shows the equipment Stetsenko allegedly used to track Russian military aircraft on behalf of Ukraine: several SDR dongles, a very dusty laptop running Airspy SDR#, an ICOM IC-R6 portable communications receiver, and various maps and charts. In short, it pretty much looks like what I can see on my own desk right now. We know little of the politics around this, but it does give one pause to consider how non-technical people view those with technical hobbies.

If you could choose a superpower to suddenly have, it really would take some careful consideration. Sure, it would be handy to shoot spider webs or burst into flames, but the whole idea of some kind of goo shooting out of your wrists seems gross, and what a nuisance to have to keep buying new clothes after every burn. Maybe just teaching yourself a new sense, like echolocation, would be a better place to start. And as it turns out, it’s not only possible for humans to echolocate, but it’s actually not that hard to learn. Researchers used a group of blind and sighted people for the test, ranging in age from 21 to 79 years, and put them through a 10-week training program to learn click-based echolocation. After getting the basics of making the clicks and listening for the returns in an anechoic chamber, participants ran through a series of tasks, like size and orientation discrimination of objects, and virtual navigation. The newly minted echolocators were also allowed out into the real world to test their skills. Three months after the study, the blind participants had mostly retained their new skill, and most of them were still using it and reported that it had improved their quality of life.

As with everything else he’s involved with, Elon Musk has drawn a lot of criticism for his Starlink satellite-based internet service. The growing constellation of satellites bothers astronomers, terrestrial ISPs are worried the service will kill their business model, and the beta version of the Starlink dish has been shown to be flakey in the summer heat. But it’s on equipment cost where Musk has taken the most flak, which seems unfair as the teardowns we’ve seen clearly show that the phased-array antenna in the Starlink dish is being sold for less than it costs to build. But still, Musk is assuring the world that Starlink home terminals will get down in the $250 to $300 range soon, and that the system could have 500,000 users within a year. There were a couple of other interesting insights, such as where Musk sees Starlink relative to 5G, and how he’s positioning Starlink to provide backhaul services to cellular companies.

Well, this is embarrassing. Last week, we mentioned that certain unlucky users of an obsolete but still popular NAS device found that their data had disappeared, apparently due to malefactors accessing the device over the internet and forcing a factory reset. Since this seems like something that should require entering a password, someone took a look at the PHP script for the factory restore function and found that a developer had commented out the very lines that would have performed the authentication:

    function get($urlPath, $queryParams=null, $ouputFormat='xml'){
//        if(!authenticateAsOwner($queryParams))
//        {
//            header("HTTP/1.0 401 Unauthorized");
//            return;
//        }

It’s not clear when the PHP script was updated, but support for MyBook Live was dropped in 2015, so this could have been a really old change. Still, it was all the hacker needed to get in and wreak havoc; interestingly, the latest attack may be a reaction to a three-year-old exploit that turned many of these devices into a botnet. Could this be a case of hacker vs. hacker?

Starlink Satellite Dish X-Rayed To Unlock RF Magic Inside

January 11, 2021 by Tom Nardi 15 Comments

When [Kenneth Keiter] took apart his Starlink dish back in November, he did his best to explain the high-level functionality of the incredibly complex device in a video posted to his YouTube channel. It was a fascinating look at the equipment, but by his own admission, he wasn’t the right person to try and explain the nuances of how the phased array actually functioned. But he knew who could do the technology justice, which is why he shipped the dismembered dish over to [Shahriar Shahramian] of The Signal Path.

Don’t be surprised if you can’t quite wrap your head around his detailed analysis after your first viewing. You’ll probably have a few lingering questions after the second re-watch as well. But that’s OK, as [Shahriar] still has a few of his own. Even after cutting out a section of the dish and putting it under an X-ray, it’s still not completely clear how the SpaceX engineers managed to cram everything into such a tidy package. Though there seems to be no question that the $500 price for the early-access hardware is an absolute steal, all things considered.

The layered antenna works on multiple frequencies.

Most of the video is spent examining the stacked honeycomb construction of the phased antenna array, which as expected, holds a number of RF secrets if you know what to look for. Put simply, there’s no such thing as an insignificant detail to the trained eye. From the carefully sized injection molded spacer sheet that keeps the upper array a specific distance from the RF4-like radome, to the almost microscopic holes that have been bored through each floating patch to maintain equalized air pressure through the stack up, [Shahriar] picks up on fascinating details which might otherwise seem like arbitrary design decisions.

But a visual inspection will only get you so far. Eventually [Shahriar] has to cut out a slice of the PCB so he can fit it into the X-ray machine, but don’t feel too bad, the dish was long dead before he got his hands on it. While he hasn’t yet completed his full analysis, an initial examination indicates that each large IC and the eight chips surrounding it make up a 16 channel beam forming module. Each channel is further split into two RX and TX pairs, which provides the necessary right and left hand polarization. That said, he admits there’s some room for interpretation and that further work would be necessary before any hard conclusions could be made.

Between this RF analysis and the initial overview provided by [Kenneth], we’ve already learned a lot more about this device than many might have expected considering how rare and expensive the hardware is. While we admit it’s not immediately clear what kind of hijinks hardware hackers could get into once this device is fully understood, we’re certainly eager to find out.

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Literally Tearing Apart A SpaceX Starlink Antenna

November 25, 2020 by Tom Nardi 85 Comments

While SpaceX’s constellation of Starlink satellites is nowhere near its projected final size, the company has enough of the birds zipping around in low Earth orbit to start a limited testing period they call the Better Than Nothing Beta. If you’re lucky enough to get selected, you have to cough up $500 for the hardware and another $100 a month for the service. Despite the fairly high bar for getting your hands on one, [Kenneth Keiter] decided to sacrifice his Starlink dish to the teardown Gods.

We say sacrifice because [Kenneth] had to literally destroy the dish to get a look inside. It doesn’t appear that you can realistically get into the exceptionally thin antenna array without pulling it all apart, thanks in part to preposterous amount of adhesive that holds the structural back plate onto the PCB. The sky-facing side of the phased array, the key element that allows the antenna to track the rapidly moving Starlink satellites as they pass overhead, is also laminated to a stack-up comprised of plastic hexagonal mesh layers, passive antenna elements, and the outer fiberglass skin. In short, there are definitely no user-serviceable parts inside.

The dish hides many secrets under its skin.

Beyond attempting to analyze the RF magic that’s happening inside the antenna, [Kenneth] also takes viewers through a tour of some of the more recognizable components of the PCB; picking out things like the Power over Ethernet magnetics, a GPS receiver, some flash storage, and the H-Bridge drivers used to control the pan and tilt motors in the base of the dish.

It also appears that the antenna is a self-contained computer of sorts, complete with ARM processor and RAM to run the software that aims the phased array. Speaking of which, it should come as no surprise to find that not only are the ICs that drive the dizzying array of antenna elements the most numerous components on the PCB, but that they appear to be some kind of custom silicon designed specifically for SpaceX.

In short, there’s still plenty we don’t know about how this high-tech receiver actually works. While [Kenneth] does a respectable job of trying to make sense of it all, and we admire the dedication required to rip apart such a rare and expensive piece of kit, it’s still going to be awhile before the hacker community truly masters the tech that SpaceX is putting into their ambitions global Internet service.

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How Does Starlink Work Anyway?

February 20, 2020 by Dan Maloney 128 Comments

No matter what you think of Elon Musk, it’s hard to deny that he takes the dictum “There’s no such thing as bad publicity” to heart. From hurling sports cars into orbit to solar-powered roof destroyers, there’s little that Mr. Musk can’t turn into a net positive for at least one of his many ventures, not to mention his image.

Elon may have gotten in over his head, though. His plan to use his SpaceX rockets to fill the sky with thousands of satellites dedicated to providing cheap Internet access ran afoul of the astronomy community, which has decried the impact of the Starlink satellites on observations, both in the optical wavelengths and further down the spectrum in the radio bands. And that’s with only a tiny fraction of the planned constellation deployed; once fully built-out, they fear Starlink will ruin Earth-based observation forever.

What exactly the final Starlink constellation will look like and what impact it would have on observations depend greatly on the degree to which it can withstand regulatory efforts and market forces. Assuming it does survive and gets built out into a system that more or less resembles the current plan, what exactly will Starlink do? And more importantly, how will it accomplish its stated goals?

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A 60 GHz Phased Array

January 31, 2020 by Al Williams 15 Comments

Our friend [Hunter Scott] gave a talk at a past Supercon about phased array antennas. He mentioned he was looking for collaborators to create an antenna with the SiBeam SB9210 chip. This is a specialized chip for WirelessHD, a more or less failed video streaming protocol, and it’s essentially an entire 60 GHz phased array on a chip with both transmit and receive capabilities. For $15, it seems like quite the bargain, and [Hunter] still wants to put the device to work.

The downside is that Lattice bought SiBeam and killed this chip — not surprising considering WirelessHD never really took off. However, [Hunter] says the chip was in some old smart TVs and laptops. If you can find replacement boards for those devices on the surplus market, you can get the chip and the supporting circuitry for a song.

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No Moving Parts: Phased Array Antennas Move While Standing Still

January 11, 2019 by Al Williams 15 Comments

If you watch old science fiction or military movies — or if you were alive back in the 1960s — you probably know the cliche for a radar antenna is a spinning dish. Although the very first radar antennas were made from wire, as radar sets moved higher in frequency, antennas got smaller and rotating them meant you could “look” in different directions. When most people got their TV with an antenna, rotating those were pretty common, too. But these days you don’t see many moving antennas. Why? Because antennas these days move electrically rather than physically using multiple antennas in a phased array. These electronically scanned phased array antennas are the subject of Hunter Scott’s talk at 2018’s Supercon. Didn’t make it? No problem, you can watch the video below.

While this seems like new technology, it actually dates back to 1905. Karl Braun fed the output of a transmitter to three monopoles set up as a triangle. One antenna had a 90 degree phase shift. The two in-phase antennas caused a stronger signal in one direction, while the out-of-phase antenna canceled most of the signal and the resulting aggregate was a unidirectional beam. By changing the antenna fed with the delay, the beam could rotate in three 120 degree steps.

Today phased arrays are in all sorts of radio equipment from broadcast radio transmitters to WiFi routers and 5G phones. The technique even has uses in optics and acoustics.

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The Engineering Of An Ultrasonic Phased Array

August 19, 2018 by Jenny List 19 Comments

Ultrasonic phased arrays are one of the wonders of the moment, with videos of small items being levitated by them shared far and wide. We’ve all seen them and some of us have even wondered about building them, but what about the practical considerations? Just how would you drive a large array of ultrasonic transducers, and how would you maintain a consistent phase relationship between their outputs? It’s a problem [Niklas Fauth] has been grappling with over the three iterations so far of his ultrasonic phased array project, and you can follow his progress on the latest build.

The arrays themselves are a 16 by 16 grid of cheap ultrasonic transducers on a PCB, fed by HV583 high-voltage shift registers. These chips have proven to be particularly problematic, their drivers having a relatively high internal resistance which leaves them prone to overheating.

An interesting solution to a problem comes from the transducers having a polarity, but because it doesn’t matter in their usual application, that polarity not being marked. He’s overcome this by using the STM32 he has managing power alongside his BeagleBone to listen through a sensor as the ‘Bone supplies each transducer in turn with a known phase. An internal map can then be created, such that the appropriate phase can be applied on a transducer-by-transducer basis.

It’s the fascination with the subject that we find appealing, this is version three and version two worked. Most of us would make one and call it a day. It’s something we’ve seen before from [Niklas], after all this is someone who plays with turbomolecular pumps for fun. Meanwhile if you would like to learn more about ultrasonic arrays and acoustic levitation, it was the subject of one of this year’s Hackaday Belgrade talks.