Day: December 10, 2024

[Wills] and his purple DIY sorting hat

From Felt To Fate: Building Your Own Sorting Hat

December 10, 2024 by 1 Comment

Ever wondered how it feels to have the Sorting Hat decide your fate? [Will Dana] wanted to find out, so he conjured a bit of Hogwarts magic, and crafted a fully animatronic Sorting Hat from scratch. In the video below, he covers every step of bringing this magical purple marvel to life—from rapid joystick movements to the electronics behind it all.

The heart of the project is two 9g servos—one actuates the mouth, and the other controls the eyebrows—powered by an ESP32 microcontroller. Communication between two ESP32 boards ensures smooth operation via the ESP-NOW protocol, making this a wireless wonder. The design process involved using mechanical advantage to solve jittery servo movements, a trick that will resonate with anyone who’s fought with uncooperative motors.

If animatronics or themed projects excite you, Hackaday has covered similar builds, from a DIY BB-8 droid to a robot fox.

Continue reading “From Felt To Fate: Building Your Own Sorting Hat” →

A Potential Exploit With The Ext Filesystem

December 10, 2024 by 12 Comments

The extended filesystem, otherwise known as ext, has been a fundamental part of Linux since before the 1.0 release in 1994. Currently the filesystem is on its fourth major revision, in use since its release in 2008 thanks to its stability, reliability, and backwards compatibility with the other ext filesystem versions. But with that much history there are bound to be a few issues cropping up here and there. [Will] recently found an exploit with this filesystem that can cause a Linux kernel to immediately panic when a manipulated USB drive is inserted into a computer.

[Will] discovered this quirk when investigating the intricacies of the filesystem for problems and other vulnerabilities. A tool called tune2fs, used for administering and modifying ext filesystems, includes the ability to pass certain commands to the Linux kernel when certain situations arise with the filesystem itself, including that the kernel should panic. One situation is that the ext filesystem itself becomes corrupted, which can then cause the kernel panic. Armed with this knowledge, a USB drive can be purposefully given a corrupted ext filesystem which, when plugged into a Linux machine, can cause the computer to shut down.

The post linked above goes into some discussion about how this exploit could be used maliciously to gain access to a Linux system, including rebooting computers where no access to a power button is otherwise enabled or making other changes to the system before needing a reboot to apply the changes. In general, though, it’s good to assume an attacker could take any route to gain access to a machine. This exploit from a few years ago, for example, allowed another Linux tool to be used to gain root access.

Thanks to [Timothy] for the tip!

Flying Drones That Can Walk And Jump Into The Air: An Idea With Legs?

December 10, 2024 by 6 Comments

When we look at how everyone’s favorite flying dinosaurs get around, we can see that although they use their wings a lot too, their legs are at least as important. Even waddling or hopping about somewhat ungainly on legs is more energy efficient than short flights, and taking off from the ground is helped by jumping into the air with a powerful leap from one’s legs. Based on this reasoning, a team of researchers set out to give flying drones their own bird-inspired legs, with their findings published in Nature (preprint on ArXiv).

The prototype RAVEN (Robotic Avian-inspired Vehicle for multiple ENvironments) drone is capable of hopping, walking, jumping onto an obstacle and jumping for take-off. This allows the drone to get into the optimal position for take-off and store energy in its legs to give it a boost when it takes to the skies. As it turned out, having passive & flexible toes here was essential for stability when waddling around, while jumping tests showed that the RAVEN’s legs provided well over 90% of the required take-off speed.

During take-off experiments the drone was able to jump to an altitude of about 0.4 meters, which allows it to clear ground-based obstacles and makes any kind of ‘runway’ unnecessary. Much like with our avian dinosaur friends the laws of physics dictate that there are strong scaling limits, which is why a raven can use this technique, but a swan or similar still requires a bit of runway instead of jumping elegantly into the air for near-vertical take-off. For smaller flying drones this approach would however absolutely seem to have legs.

Continue reading “Flying Drones That Can Walk And Jump Into The Air: An Idea With Legs?” →

3D Printer Eliminates The Printer Bed

December 10, 2024 by 18 Comments

Anyone who has operated a 3D printer before, especially those new to using these specialized tools, has likely had problems with the print bed. The bed might not always be the correct temperature leading to problems with adhesion of the print, it could be uncalibrated or dirty or cause any number of other issues that ultimately lead to a failed print. Most of us work these problems out through trial and error and eventually get settled in, but this novel 3D printer instead removes the bed itself and prints on whatever surface happens to be nearby.

The printer is the product of [Daniel Campos Zamora] at the University of Washington and is called MobiPrint. It uses a fairly standard, commercially available 3D printer head but attaches it to the base of a modified robotic vacuum cleaner. The vacuum cleaner is modified with open-source software that allows it to map its environment without the need for the manufacturer’s cloud services, which in turn lets the 3D printer print on whichever surface the robot finds in its travels. The goal isn’t necessarily to eliminate printer bed problems; a robot with this capability could have many more applications in the realm of accessibility or even, in the future, printing while on the move.

There were a few surprising discoveries along the way which were mentioned in an IEEE Spectrum article, as [Campos Zamora] found while testing various household surfaces that carpet is surprisingly good at adhering to these prints and almost can’t be unstuck from the prints made on it. There are a few other 3D printers out there that we’ve seen that are incredibly mobile, but none that allow interacting with their environment in quite this way.

Continue reading “3D Printer Eliminates The Printer Bed” →

Trying To Shatter The World’s Fastest RC Car Record

December 10, 2024 by 11 Comments
The RC car is controlled via an FPV setup. (Credit: Luke Bell, YouTube)

Fresh off a world record for the fastest quadcopter, [Luke Bell] decided to try his luck with something more own to earth, namely trying to tackle the world record for the fastest RC car, with the current record set at 360 km/h. Starting off with a first attempt in what will be a video series, the obvious approach seems to be to get some really powerful electric motors, a streamlined body and a disused runway to send said RC car hurtling along towards that golden medal. Of course, if it was that easy, others would have done it already.

With the quadcopter record of nearly 500 km/h which we covered previously, the challenge was in a way easier, as other than air resistance and accidental lithobraking there are no worries about ground texture, tire wear or boundary layer aerodynamics. In comparison, the RC car has to contend with all of these, with the runway’s rough tarmac surface being just one of the issues, along with making sure that the wheels would hold up to the required rotation speed. For the wheels you got options like foam, hard rubber, etc., all with their own advantages and disadvantages, mostly in terms of grip and reliability.

So far speeds of over 200 km/h are easy enough to do, with foam wheels being the preferred option. To push the RC car to 300 km/h and beyond, a lot more experimentation and trial runs will have to be performed. Pending are changes to the aerodynamic design with features also commonly seen in F1 race cars such as downforce spoilers, diffusers and other tricks which should prevent the RC car from (briefly) becoming an RC airplane.

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2025 Hackaday Europe CFP: We Want You!

December 10, 2024 by 3 Comments

Hackaday’s Supercon is still warm in our hearts, and the snow is just now starting to fall, but we’re already looking forward to Spring. Or at least to Hackaday Europe, which will be taking place March 15th and 16th in Berlin, Germany.

Tickets aren’t on sale yet, but we know a way that you can get in for free.

Call for Participation

What makes Hackaday Europe special? Well, it’s you! We’re excited to announce that we’re opening up our call for talks right now, and we can’t wait to hear what you have to say. Speakers of course get in free, but the real reason that you want to present is whom you’re presenting to.

The Hackaday audience is interested, inquisitive, and friendly. If you have a tale of hardware, firmware, or software derring-do that would only really go over with a Hackaday crowd, this is your chance. We have slots open for shorter 20-minute talks as well as longer 40-minute ones, so whether you’ve got a quick hack or you want to take a deep dive, we’ve got you covered. We especially love to hear from new voices, so if you’ve never given a talk about your projects before, we’d really encourage you to apply!

Continue reading “2025 Hackaday Europe CFP: We Want You!” →

Creating A Radiation King Radio In The Real World

December 10, 2024 by 13 Comments

If you’re a fan of the Fallout series of games, you’ve probably come across a Radiation King radio before. In the game, that is, they don’t exist in real life. Which is precisely why [zapwizard] built one!

Externally, the design faithfully recreates the mid-century design of the Radiation King. It’s got the louvered venting on the front panel, the chunky knobs, and a lovely analog needle dial, too. Inside, it’s got a Raspberry Pi Zero which is charged with running the show and dealing with audio playback. It’s paired with a Pi Pico, which handles other interface tasks.

It might seem simple, but the details are what really make this thing shine. It doesn’t just play music, it runs a series of simulated radio stations which you can “tune into” using the radio dial. [zapwizard dives into how it all works—from the air core motor behind the simulated tuning dial, to the mixing of music and simulated static. It’s really worth digging into if you like building retro-styled equipment that feels more like the real thing.

It’s not just a prop—it’s a fully-functional item from the Fallout universe, made manifest. You know how much we love those. If you’re cooking up your own post-apocalyptic hacks, fictional or non-fictional, don’t hesitate to let us know.