Displays We Like Hacking: HDMI

June 5, 2024 by 26 Comments

I don’t like HDMI. Despite it being a pretty popular interface, I find crucial parts of it to be alien to what hackers stand for. The way I see it, it manages to be proprietary while bringing a lot of the old cruft in. It doesn’t have a native alternative like DisplayPort, so portable implementations tend to suffer power-wise; the connector situation is interesting, and the HDMI Foundation has been doing some weird stuff; in particular, they are pretty hostile to open-source technology.

This article is not the place for such feelings, however, especially since I’ve expressed them enough in the DisplayPort article. We the hackers deserve to be able to handle the interfaces we stumble upon, and I firmly believe in that way more than in my right to animosity towards HDMI.

The HDMI interface is seriously prominent wherever you look, in part because it’s the interface created by the multimedia-involved companies for the multimedia-involved companies. Over the years we’ve had it, it’s been more than sufficient for basically everything we do video-wise, save for the highest resolutions.

It’s also reasonably simple to wire up, hack on, and even bitbang. Let’s go through what makes it tick.

The Core

HDMI is, at its core, three differential pairs for data, plus one pair to clock them and in the darkness bind them. It’s a digital interface, though it is a fun one. This makes it way more suitable for higher-distance video transmissions than interfaces like VGA, and as long as you stick to relatively low resolutions, HDMI won’t have as many asks in terms of PCB layout as DisplayPort might, thanks to HDMI link speeds scaling proportionally with the display resolution.

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Gears Are Old And Busted, Capstans Are Cool

June 3, 2024 by 44 Comments

Zero backlash, high “gear” reduction, high torque transparency, silent operation, and low cost. What is this miracle speed reduction technology, you ask? Well, it’s shoelaces and a bunch of 3D printed plastic, at least in [Aaed Musa]’s latest installment in his series on developing his own robot dog.

OK, the shoelaces were only used in the first proof of concept. [Aaed] shortly upgrades to steel cable, and finds out that steel fatigues and snaps after a few hours. He settles on Dyneema DM-20, a flexible yet non-stretching synthetic rope.

Before it’s all over, he got a five-bar linkage plotting with a pencil on the table and a quadriped leg jumping up and down on the table — to failure. All in all, it points to a great future, and we can’t wait to see the dog-bot that’s going to come out of this.

There’s nothing secret about using capstan drives, but we often wonder why we don’t see cable-powered robotics used more in the hacker world. [Aaed] makes the case that it pairs better with 3D printing than gears, where the surface irregularities really bind. If you want to get a jumpstart, the test fixture that he’s using is available on GitHub.

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Tech In Plain Sight: Theodolites

June 3, 2024 by 23 Comments

We take it for granted that you can look at your phone and tell exactly where you are. At least, as exact as the GPS satellites will allow. But throughout human history, there has been a tremendous desire to know where here is, exactly. Where does my farm end and yours start? Where is the border of my city or country? Suppose you have a flagpole directly in the center of town and a clock tower at the edge of town. You know where they are precisely on a map. You also know how tall they are. What you need is a theodolite, which is an instrument that measures angles very precisely.

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A Treasure Trove In An English Field

June 3, 2024 by 12 Comments

This is being written in a tent in a field in Herefordshire, one of the English counties that borders Wales. It’s the site of Electromagnetic Field, this year’s large European hacker camp, and outside my tent the sky is lit by a laser light show to the sound of electronic music. I’m home.

One of the many fun parts of EMF is its swap table. A gazebo to which you can bring your junk, and from which you can take away other people’s junk. It’s an irresistible destination which turns a casual walk into half an hour pawing through the mess in search of treasure, and along the way it provides an interesting insight into technological progress. What is considered junk in 2024?

Something for everyone

As always, the items on offer range from universal treasures of the I-can’t-believe-they-put that-there variety, through this-is-treasure-to-someone-I’m-sure items, to absolute junk. Some things pass around the camp like legends; I wasn’t there when someone dropped off a box of LED panels for example, but I’ve heard the story relayed in hushed tones several times since, and even seen some of the precious haul. A friend snagged a still-current AMD processor and some Noctua server fans as another example, and I’m told that amazingly someone deposited a Playstation 5. But these are the exceptions, in most cases the junk is either very specific to something, or much more mundane. I saw someone snag an audio effects unit that may or may not work, and there are PC expansion cards and outdated memory modules aplenty.

Finally, there is the absolute junk, which some might even call e-waste but I’ll be a little more charitable about. Mains cables, VGA cables, and outdated computer books. Need to learn about some 1990s web technology? We’ve got you covered. Continue reading “A Treasure Trove In An English Field” →

Using The Moiré Effect For Unique Clock Face

June 3, 2024 by 13 Comments

If you’ve ever seen artifacts on a digital picture of a computer monitor, or noticed an unsettling shifting pattern on a TV displaying someone’s clothes which have stripes, you’ve seen what’s called a Moiré pattern where slight differences in striping of two layers create an emergent pattern. They’re not always minor annoyances though; in fact they can be put to use in all kinds of areas from art to anti-counterfeiting measures. [Moritz] decided to put a few together to build one of the more unique clock displays we’ve seen.

The clock itself is made of four separate Moiré patterns. The first displays the hours with a stretching pattern, the second and third display the minutes with a circular pattern, and the seconds are displayed with a a spiral type. The “hands” for the clock are 3D printed with being driven by separate stepper motors with hall effect sensors for calibration so that the precise orientation of the patterns can be made. A pair of Arduinos control the clock with the high-accuracy DS3231 module keeping track of time, and [Moritz] built a light box to house the electronics and provide diffuse illumination to the display.

Moiré patterns can be used for a number of other interesting use cases we’ve seen throughout the years as well. A while back we saw one that helps ships navigate without active animations or moving parts and on a much smaller scale they can also be used for extremely precise calipers.

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Use That One Port For High-Speed FPGA Data Export

June 1, 2024 by 7 Comments

There’s a good few options for exporting data out of FPGAs, like Ethernet, USB2, or USB3. Many FPGAs have a HDMI (or rather, sparkling DVI) port as well, and [Steve Markgraf] brings us the hsdaoh project — High-Speed Data Acquisition Over HDMI, using USB3 capture cards based on the Macrosilicon MS2130 chipset to get the data from the FPGA right to your PC.

Current FPGA-side implementation is designed for Sipeed Tang chips and the GOWIN toolchain, but it should be portable to an open-source toolchain in the future. Make sure you’re using a USB3 capture card with a MS2130 chipset, load the test code into your FPGA, run the userspace capture side, and you’re ready to add this interface to your FPGA project! It’s well worth it, too – during testing, [Steve] has got data transfer speeds up to 180 MB/s, without the USB3 complexity.

As a test, [Steve] shows us an RX-only SDR project using this interface, with respectable amounts of bandwidth. The presentation goes a fair bit into the low-level details of the protocol, from HDMI fundamentals, to manipulating the MS2130 registers in a way that disables all video conversion; do watch the recording, or at least skim the slides! Oh, and if you don’t own a capture card yet, you really should, as it makes for a wonderful Raspberry Pi hacking companion in times of need.

This Week In Security: Operation Endgame, Appliance Carnage, And Router Genocide

May 31, 2024 by 3 Comments

This week saw an impressive pair of takedowns pulled off by law enforcement agencies around the world. The first was the 911 S5 botnet, Which the FBI is calling “likely the world’s largest botnet ever”. Spreading via fake free VPN services, 911 was actually a massive proxy service for crooks. Most lately, this service was operating under the name “Cloud Router”. As of this week, the service is down, the web domain has been seized, and the alleged mastermind, YunHe Wang, is in custody.

The other takedown is interesting in its own right. Operation Endgame seems to be psychological warfare as well as actual arrests and seizures. The website features animated shorts, a big red countdown clock, and a promise that more is coming. The actual target was the ring that manage malware droppers — sort of middlemen between initial shellcode, and doing something useful with a compromised machine. This initial volley includes four arrests, 100+ servers disrupted, and 2,000+ domains seized.

The arrests happened in Armenia and Ukraine. The messaging around this really seems to be aimed at the rest of the gang that’s out of reach of law enforcement for now. Those criminals may still be anonymous, or operating in places like Russia and China. The unmistakable message is that this operation is coming for the rest of them sooner or later. Continue reading “This Week In Security: Operation Endgame, Appliance Carnage, And Router Genocide” →