Displays We Love Hacking: DSI

We would not be surprised if DSI screens made up the majority of screens on our planet at this moment in time. If you own a smartphone, there’s a 99.9% chance its screen is DSI. Tablets are likely to use DSI too, unless it’s eDP instead, and a smartwatch of yours definitely will. In a way, DSI displays are inescapable.

This is for a good reason. The DSI interface is a mainstay in SoCs and mobile CPUs worth their salt, it allows for higher speeds and thus higher resolutions than SPI ever could achieve, comparably few pins, an ability to send commands to the display’s controller unlike LVDS or eDP, and staying low power while doing all of it.

There’s money and power in hacking on DSI – an ability to equip your devices with screens that can’t be reused otherwise, building cooler and cooler stuff, tapping into sources of cheap phone displays. What’s more, it’s a comparably underexplored field, too. Let’s waste no time, then!

Decently Similar Internals

DSI is an interface defined by the MIPI Alliance, a group whose standards are not entirely open. Still, nothing is truly new under the sun, and DSI shares a lot of concepts with interfaces we’re used to. For a start, if you remember DisplayPort internals, there are similarities. When it comes to data lanes, DSI can have one, two or four lanes of a high-speed data stream; smaller displays can subsist with a single-lane, while very high resolution displays will want all four. This is where the similarities end. There’s no AUX to talk to the display controller, though – instead, the data lanes switch between two modes.

Continue reading “Displays We Love Hacking: DSI”

Scrapping The Local Loop, By The Numbers

A few years back I wrote an “Ask Hackaday” article inviting speculation on the future of the physical plant of landline telephone companies. It started innocently enough; an open telco cabinet spotted during my morning walk gave me a glimpse into the complexity of the network buried beneath my feet and strung along poles around town. That in turn begged the question of what to do with all that wire, now that wireless communications have made landline phones so déclassé.

At the time, I had a sneaking suspicion that I knew what the answer would be, but I spent a good bit of virtual ink trying to convince myself that there was still some constructive purpose for the network. After all, hundreds of thousands of technicians and engineers spent lifetimes building, maintaining, and improving these networks; surely there must be a way to repurpose all that infrastructure in a way that pays at least a bit of homage to them. The idea of just ripping out all that wire and scrapping it seemed unpalatable.

With the decreasing need for copper voice and data networks and the increasing demand for infrastructure to power everything from AI data centers to decarbonized transportation, the economic forces arrayed against these carefully constructed networks seem irresistible. But what do the numbers actually look like? Are these artificial copper mines as rich as they appear? Or is the idea of pulling all that copper out of the ground and off the poles and retasking it just a pipe dream?

Continue reading “Scrapping The Local Loop, By The Numbers”

Switching Regulator Layout For Dummies

Last time, we went over switching regulator basics – why they’re wonderful, how do you find a switching regulator chip for your purpose, and how to easily pick an inductor for one. Your datasheet should also tell you about layout requirements. However, it might not, or you might want to deviate from them – let’s go more in-depth on what those requirements are about.

Appreciate The Feedback

The two resistors on the right decide what your output voltage will be, and their output is noise-sensitive

There’s a few different switching regulator topologies. Depending on your regulator’s topology and how many components your chip contains, you might need some external components – maybe a Schottky diode, maybe a FET, or maybe even a FET pair. It’s often that the FET is built-in, and same goes for diodes, but with higher-current regulator (2 A to 3 A and above), it’s not uncommon to require an external one. For sizing up those, you’ll want to refer to the datasheet or existing boards.

Another thing is input and output capacitors – don’t skimp on those, because some regulators are seriously sensitive to the amount of capacitance they’re operating with. Furthermore, if you fail to consider things like capacitance dropping with voltage, you might make your regulator very unhappy – not that a linear regulator would be happy either, to be clear. We’ve covered an explainer on this recently – do check it out!

One thing you will likely need, is a feedback resistor divider – unless your switching regulator is pre-set for a certain voltage or is digitally controlled, you need to somehow point it to the right voltage, in an analog way. Quite a few switching regulators are set for a certain voltage output, but most of them aren’t, and they will want you to add a resistor divider to know what to output. There’s usually a formula for resistor divider calculation, so, pick a common resistor value, put it in as one of the resistors into the formula, get the other resistor value out of that formula, and see what’s the closest value you can actually buy. Don’t go below about 10 kΩ so that you don’t have unnecessary idle power consumption, but also don’t go too far above 100 kΩ to ensure good stability of the circuit. Continue reading “Switching Regulator Layout For Dummies”

Hackaday Links Column Banner

Hackaday Links: June 9, 2024

We’ve been harping a lot lately about the effort by carmakers to kill off AM radio, ostensibly because making EVs that don’t emit enough electromagnetic interference to swamp broadcast signals is a practical impossibility. In the US, push-back from lawmakers — no doubt spurred by radio industry lobbyists — has put the brakes on the move a bit, on the understandable grounds that an entire emergency communication system largely centered around AM radio has been in place for the last seven decades or so. Not so in Japan, though, as thirteen of the nation’s 47 broadcasters have voluntarily shut down their AM transmitters in what’s billed as an “impact study” by the Ministry of Internal Affairs and Communications. The request for the study actually came from the broadcasters, with one being quoted in a hearing on the matter as “hop[ing] that AM broadcasting will be promptly discontinued.” So the writing is apparently on the wall for AM radio in Japan.

Continue reading “Hackaday Links: June 9, 2024”

Happy Birthday, Tetris!

Porting DOOM to everything that’s even vaguely Turing complete is a sport for the advanced hacker. But if you are just getting started, or want to focus more on the physical build of your project, a simpler game is probably the way to go. Maybe this explains the eternal popularity of games like PONG, Tetris, Snake, or even Pac-Man. The amount of fun you can have playing the game, relative to the size of the code necessary to implement them, make these games evergreen.

Yesterday was Tetris’ 40th birthday, and in honor of the occasion, I thought I’d bring you a collection of sweet Tetris hacks.

On the big-builds side of things, it’s hard to beat these MIT students who used colored lights in the windows of the Green Building back in 2012. They apparently couldn’t get into some rooms, because they had some dead pixels, but at that scale, who’s complaining? Coming in just smaller, at the size of a whole wall, [Oat Foundry]’s giant split-flap display Tetris is certainly noisy enough.

Smaller still, although only a little bit less noisy, this flip-dot Tetris is at home on the coffee table, while this one by [Electronoobs] gives you an excuse to play around with RGB LEDs. And if you need a Tetris for your workbench, but you don’t have the space for an extra screen, this oscilloscope version is just the ticket. Or just play it (sideways) on your business card.

All of the above projects have focused on the builds, but if you want to tackle your own, you’ll need to spend some time with the code as well. We’ve got you covered. Way back, former Editor in Chief [Mike Szczys] ported Tetris to the AVR platform. If you need color, this deep dive into the way the NES version of Tetris worked also comes with demo code in Java and Lua. TetrOS is the most minimal version of the game we’ve seen, coming in at a mere 446 bytes, but it’s without any of the frills.

No Tetris birthday roundup would be complete without mentioning the phenomenal “From NAND to Tetris” course, which really does what it says on the package: builds a Tetris game, and your understanding of computing in general, from the ground up.

Can you think of other projects to celebrate Tetris’ 40th? We’d love to see your favorites!

Hackaday Podcast Episode 274: Capstan Robots, Avionics Of Uncertain Purpose, And What The Frack?

What do capstans, direct conversion receivers, and fracking have in common? They were all topics Hackaday editors Elliot Williams and Al Williams found fascinating this week. If you wonder what makes an electrical ground a ground, or what a theodolite is, you should check it out.

This week, the hacks came fast and furious. Capstans, instead of gears, work well for 3D-printed mechanisms, a PI Pico can directly receive radio signals, and the guys saw a number of teardowns and reverse engineering triumphs. You’ll also find solid-state heat pumps, flying wings, spectroscopy, and more.

The can’t miss articles this week? Learn about theodolites, a surveying feat from ancient Greece, and how fracking works.

Check out the links below if you want to follow along, and as always, tell us what we’ve mispronounced — or any other thoughts on the episode — in the comments!

Download an archival copy for your personal collection.

Continue reading “Hackaday Podcast Episode 274: Capstan Robots, Avionics Of Uncertain Purpose, And What The Frack?”

This Week In Security: Recall, Modem Mysteries, And Flipping Pages

Microsoft is racing to get into the AI game as part of Windows 11 on ARM, calling it Copilot+. It’s an odd decision, but clearly aimed at competing with the Apple M series of MacBooks. Our focus of interest today is Recall, a Copilot+ feature that not only has some security problems, but also triggers a sort of visceral response from regular people: My computer is spying on me? Eww.

Yes, it really sort of is. Recall is a scheme to take screen shots of the computer display every few seconds, run them through character recognition, and store the screenshots and results in a database on the local machine hard drive. There are ways this could be useful. Can’t remember what website had that recipe you saw? Want to revisit a now-deleted tweet? Is your Google-fu failing you to find a news story you read last week? Recall saw it, and Recall remembers. But what else did Recall see? Every video you watched, ever website you visited, and probably some passwords and usernames you typed in.

Continue reading “This Week In Security: Recall, Modem Mysteries, And Flipping Pages”