Just a simple Lego bouncy DVD logo screensaver mechanism. (Credit: Grant Davis, YouTube)

Building The DVD Logo Screensaver With LEGO

The completed Lego DVD screensaver. (Credit: Grant Davis, YouTube)
The completed Lego DVD screensaver. (Credit: Grant Davis, YouTube)

There’s something extremely calming and pleasing about watching a screensaver that merely bounces some kind of image around, with the DVD logo screensaver of a DVD player being a good example. The logical conclusion is thus that it would be great to replicate this screensaver in Lego, because it’d be fun and easy. That’s where [Grant Davis]’s life got flipped upside-down, as this turned out to be anything but an easy task in his chosen medium.

Things got off on a rocky start with figuring out how to make the logo bounce against the side of the ‘screen’, instead of having it merely approach before backing off. The right approach here seemed to be Lego treads as used on e.g. excavators, which give the motion that nice pause before ‘bouncing’ back in the other direction.

With that seemingly solved, most of the effort went into assembling a functional yet sturdy frame, all driven by a single Lego Technic electromotor. Along the way there were many cases of rapid self-disassembly, ultimately leading to a complete redesign using worm gears, thus requiring running the gears both ways with help from a gearbox.

Since the screensaver is supposed to run unattended, many end-stop and toggle mechanisms were tried and discarded before settling on the design that would be used for the full-sized build. Naturally, scaling up always goes smoothly, so everything got redesigned and beefed up once again, with more motors added and multiple gearbox design changes attempted after some unfortunate shredded gears.

Ultimately [Grant] got what he set out to do: the DVD logo bouncing around on a Lego ‘TV’ in a very realistic fashion, set to the noise of Lego Technic gears and motors whirring away in the background.

Thanks to [Carl Foxmarten] for the tip.

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Diagram of C99 designated initializers.

Tips For C Programming From Nic Barker

If you’re going to be a hacker, learning C is a rite of passage. If you don’t have much experience with C, or if your experience is out of date, you very well may benefit from hearing [Nic Barker] explain tips for C programming.

In his introduction he notes that C, invented in the 70s by Dennis Ritchie, is now more than 50 years old. This old language still appears in lists of the most popular languages, although admittedly not at the top!

He notes that the major versions of C, named for the year they were released, are: C89, C99, C11, and C23. His recommendation is C99 because it has some features he doesn’t want to live without, particularly scoped variables and initializing structs with named members using designated initializers. Also C89 is plagued with non-standard integer types, and this is fixed by stdint.h in C99. Other niceties of C99 include compound literals and // for single-line comments.

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Building A Diwheel To Add More Tank Controls To Your Commute

It’s often said that one should not reinvent the wheel, but that doesn’t mean that you cannot change how the use of said wheel should be interpreted. After initially taking the rather zany concept of a monowheel for a literal ride, [Sam Barker] decided to shift gears, did a ‘what if’ and slapped a second monowheel next to the first one to create his diwheel vehicle. Using much thicker steel for the wheels and overall much more robust construction than for his monowheel, the welding could commence.

It should be said here that the concept of a diwheel, or dicycle, isn’t entirely new, but the monowheel – distinct from a unicycle – is much older, with known builds at least as far back as the 19th century. Confusing, self-balancing platforms like Segways are also referred to as ‘dicycles’, while a diwheel seems to refer specifically to what [Sam] built here. That said, diwheels are naturally stable even without gyroscopic action, which is definitely a big advantage.

The inner frame for [Sam]’s diwheel is built out of steel too, making it both very robust and very heavy. High-tech features include suspension for that smooth ride, and SLS 3D-printed nylon rollers between the inner frame and the wheels. After some mucking about with a DIY ‘lathe’ to work around some measurement errors, a lot more welding and some questionable assembly practices, everything came together in the end.

This is just phase one, however, as [Sam] will not be installing pedals like it’s an old-school monowheel. Instead it’ll have electrical drive, which should make it a bit less terrifying than the Ford Ka-based diwheel we featured in 2018, but rather close to the electric diwheel called EDWARD which we featured back in 2011. We hope to see part two of this build soon, in which [Sam] will hopefully take this beast for its first ride.

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JawnCon Returns This Weekend

For those local to the Philadelphia area, a “jawn” can be nearly anything or anyone — and at least for this weekend, it can even be a hacker con building up steam as it enters its third year. Kicking off this Friday at Arcadia University, JawnCon0x2 promises to be another can’t-miss event for anyone with a curious mind that lives within a reasonable distance of the Liberty Bell.

The slate of talks leans slightly towards the infosec crowd, but there’s really something for everyone on the schedule. Presentations such as Nothing is Safe: An Introduction to Hardware (In)Security and Making the GameTank – A New, Real 8-Bit Game Machine will certainly appeal to those of us who keep a hot soldering iron within arm’s reach, while Rolling Recon & Tire Prints: Perimeter Intrusion Detection and Remote Shenanigans via Rogue Tire Stem RF and Get More Radio Frequency Curious will certainly appeal to the radio enthusiasts.

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Qualcomm Introduces The Arduino Uno Q Linux-Capable SBC

Generally people equate the Arduino hardware platforms with MCU-centric options that are great for things like low-powered embedded computing, but less for running desktop operating systems. This looks about to change with the Arduino Uno Q, which keeps the familiar Uno formfactor, but features both a single-core Cortex-M33 STM32U575 MCU and a quad-core Cortex-A53 Qualcomm Dragonwing QRB2210 SoC.

According to the store page the board will ship starting October 24, with the price being $44 USD. This gets you a board with the aforementioned SoC and MCU, as well as 2 GB of LPDDR4 and 16 GB of eMMC. There’s also a WiFi and Bluetooth module present, which can be used with whatever OS you decide to install on the Qualcomm SoC.

This new product comes right on the heels of Arduino being acquired by Qualcomm. Whether the Uno Q is a worthy purchase mostly depends on what you intend to use the board for, with the SoC’s I/O going via a single USB-C connector which is also used for its power supply. This means that a USB-C expansion hub is basically required if you want to have video output, additional USB connectors, etc. If you wish to run a headless OS install this would of course be much less of a concern.

2025 Hackaday Supercon: More Wonderful Speakers

Supercon is just around the corner, and we’re absolutely thrilled to announce the second half of our slate! Supercon will sell out so get your tickets now before it’s too late. If you’re on the fence, we hope this pushes you over the line. And if it doesn’t, stay tuned — we’ve still got to tell you everything about the badge and the fantastic keynote speaker lineup.

(What? More than one keynote speaker? Unheard of!)

And as if that weren’t enough, there’s delicious food, great live music, hot soldering irons, and an absolutely fantastic crowd of the Hackaday faithful, and hopefully a bunch of new folks too. If you’re a Supercon fan, we’re looking forward to seeing you again, and if it’s your first time, we’ll be sure to make you feel welcome. Continue reading “2025 Hackaday Supercon: More Wonderful Speakers”