An Electric Unicycle, In Minimalist Form

September 1, 2023 by Jenny List 18 Comments

When self balancing scooters hit the market a few years ago they brought alongside them a range of machines, from the hoverboard kids toys which have provided so many useful parts, to the stand-astride electric unicycles. These last machines have a bulky battery and controller box atop the wheel, and [Dycus] set his sights on this by transferring it to a backpack with the vehicle’s IMU sensor relocated to one of the pedals.

Such a job is not merely a simple case of rewiring with some longer cables, as a first challenge the IMU communicates via I2C which isn’t suitable for longer distances. This is solved by a chipset which places the I2C on a differential pair, but even then it’s not quite a case of stepping on and zipping about. The PID parameters of the balancing algorithm on a stock machine are tuned for the extra weight of the battery on top, and these needed to be modified. Fortunately there have been enough people hacking the STM microcontroller and firmware involved for this task to be achievable, but we’d rate it as still something not for the faint-hearted.

The final result can be seen in the video below, and the quality of the physical work shows as very high. The former battery box is repurposed into a stylish backpack, and though the newly minimalist foot pedals and wheel are a little less easy to get going he zips around with ease.

Hungry for more? This ain’t the first we’ve shown you.

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Hackaday Prize 2023: 10 KW Electronic Load

September 1, 2023 by Dave Rowntree 22 Comments

[tinfever] needed a high-power benchtop electronic load for an upcoming project, and by their own admission decided foolishly to build their own. And we’re glad they did. The thing is, whilst this isn’t exactly a super-cheap project to build, buying a commercial offering with a capability of 10 kW and up to 30 kW pulsed, is going to cost an absolute fortune.

Built inside a cubic frame using what appears to be standard 2020 aluminum rails and fixturing, the modular construction is nice and clean, with plenty of space around the load boards to allow the cooling air to circulate.

The operating principle is very simple; custom PCBs act in parallel to provide any load needed, by switching in the on-board load resistor. Each load board handles all the details of switching and dumping the power due to the inductance in the system wiring and the wire-wound resistors themselves.

Whilst we know that wire-wound resistors are reverse-wound to minimize inductance, there will still be some, and each load board will contribute a little more when the whole system is scaled up. Also, each load PCB handles its own temperature sensing, and current measurement passing these data off to the control PCB. A front-end connector PCB provides a variety of connection options to interface to the DUT (Device Under Test.) The system controller is based around an STM32 processor which deals with quite a lot more than you might think is needed on a first look.

The sense currents from each load need to be sensed, scaled, and summed to keep the overall load accuracy within the 1% spec. Also, it is on duty for PWM control of the cooling fans, handling the user interface, and any other remote connectivity. There are a lot of details on the project page, as we’re only skimming the surface here. If you’re interested in building an active load, this is a project you really should be digging into.

We shall watch with interest for when [tinfever] scales up this eight-slot prototype to the full specification of 52 stages! When working with power applications, there comes a point when you really need an electronic load, and to that end, here’s one with a very specific use case to get you started.

There is also the option of buying something cheap from the usual sources and hacking on some custom firmware to adapt it a little to your needs.

On Vim, Modal Interfaces And The Way We Interact With Computers

September 1, 2023 by Maya Posch 65 Comments

The ways in which we interact with computers has changed dramatically over the decades. From flipping switches on the control panels of room-sized computers, to punching holes into cards, to ultimately the most common ways that we interact with computers today, in the form of keyboards, mice and touch screens. The latter two especially were developed as a way to interact with graphical user interfaces (GUI) in an intuitive way, but keyboards remain the only reasonable way to quickly enter large amounts of text, which raises many ergonomic questions about how to interact with the rest of the user interface, whether this is a command line or a GUI.

For text editors, perhaps the most divisive feature is that of modal versus non-modal interaction. This one point alone underlies most of the Great Editor War that has raged since time immemorial. Practically, this is mostly about highly opiniated people arguing about whether they like Emacs or vi (or Vim) better. Since in August of 2023 we said our final farewell to the creator of Vim – Bram Moolenaar – this might be a good point to put down the torches and pitchforks and take a sober look at why Vim really is the logical choice for fast, ergonomic coding and editing.

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Hackaday Podcast 234: Machines On Fire, Old Kinect New Kinect, And Birth Of The Breadboard

September 1, 2023 by Tom Nardi 6 Comments

It might sound like a joke, but this week, Elliot Williams and Tom Nardi start things off by asking how you keep a Polish train from running. Like always, the answer appears to be a properly modulated radio signal. After a fiery tale about Elliot’s burned beans, the discussion moves over to the adventure that is home CNC ownership, the final chapter in the saga of the Arecibo Telescope, and the unexpected longevity of Microsoft’s Kinect. Then it’s on to the proper way to cook a PCB, FFmpeg in the browser, and a wooden cyberdeck that’s worth carrying around. Finally, they’ll go over the next generation of diode laser engravers, and take a look back at the origins of the lowly breadboard.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Download it yourself. You don’t need the cloud!

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Motorized Camera Slider Rides On Carbon

September 1, 2023 by Bryan Cockfield 1 Comment

While not every camera mount needs to have six degrees of freedom, one or two can be extremely helpful in the photographic world. In order to make time-lapse shots with some motion or shots that incorporate some parallax, a moving camera mount or dolly is needed, and this small one builds upon a pre-existing, although non-motorized, camera slider.

The slider is an inexpensive model from everyone’s favorite online warehouse, with rails that are at least coated in carbon, if not made out of it entirely, to ensure smooth camera motion. To add the motorization to automatically move the camera, a stepper motor with a belt drive is used which is controlled by an Arduino. A few limit switches are added, letting the dolly perform different movement patterns automatically, and a pair of potentiometers for fine and coarse speed control are included as well, letting the camera take both time-lapse and video while using this mount at various controllable speeds.

With everything tucked into a relatively small box at one end of the dolly, the build is both accessible and functional. The code for the microcontroller is also available on the project’s GitHub page for anyone looking to replicate or build upon the project. And, for those looking to add more degrees of freedom to their camera setups, take a look at this DIY pan and tilt mount.

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This Week In Security: Not A Vulnerability, BGP Bug Propogation, And Press Enter To Hack

September 1, 2023 by Jonathan Bennett 6 Comments

Curl was recently notified of a CVE, CVE-2020-19909, rated at a hair-raising 9.8 on the CVSS scale. And PostgreSQL has CVE-2020-21469, clocking in with a 7.5 severity. You may notice something odd about those two vulnerabilities, but I promise the 2020 date is only the tip of the iceberg here.

Let’s start with PostgreSQL. That vulnerability was only present in version 12.2, which released in February of 2020, and was fixed with the 12.3 release in May of that same year. The problem is a stack buffer overflow, which doesn’t seem to enable code execution, but does cause a denial of service situation. To trigger the bug? Repeatedly send the PostgreSQL daemon the SIGHUP signal.

If you’re familiar with Linux signals, that might sound odd. See, the SIGHUP signal technically indicates the end of a user session, but most daemons use it to indicate a restart or reload request. And to send this signal, a user has to have elevated privileges — elevated enough to simply stop the daemon altogether. Put simply, it’s not a security vulnerability, just a minor bug.

And now on to curl — This one is just bizarre. The issue is a integer overflow in the --retry-delay argument, which specifies in seconds how often curl should retry a failing download. The value is multiplied by 1000 to convert to milliseconds, resulting in an overflow for very large values. The result of that overflow? A smaller value for the retry delay.

[Daniel Stenberg] makes the point that this tale is a wonderful demonstration of the brokenness of the CVE system and NVD’s handling of it. And in this case, it’s hard not to see this as negligence. We have to work really hard to construct a theoretical scenario where this bug could actually be exploited. The best I’ve been able to come up with is an online download tool, where the user can specify part of the target name and a timeout. If that tool had a check to ensure that the timeout was large enough to avoid excess traffic, this bug could bypass that check. Should we be assigning CVEs for that sort of convoluted, theoretical attack?

But here’s the thing, that attack scenario should rate something like a CVSS of 4.8 at absolute worst. NVD assigned this a 9.8. There’s no way you can squint at this bug hard enough to legitimately rank it that severe. At the time of writing, the NVD lists this as “UNDERGOING REANALYSIS”.
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Re-Creating Pink Floyd In The Name Of Speech

September 1, 2023 by Kristina Panos 18 Comments

For people who have lost the ability to speak, the future may include brain implants that bring that ability back. But could these brain implants also allow them to sing? Researchers believe that, all in all, it’s just another brick in the wall.

In a new study published in PLOS Biology, twenty-nine people who were already being monitored for epileptic seizures participated via a postage stamp-sized array of electrodes implanted directly on the surface of their brains. As the participants were exposed to Pink Floyd’s Another Brick In the Wall, Part 1, the researchers gathered data from several areas of the brain, each attuned to a different musical element such as harmony, rhythm, and so on. Then the researchers used machine learning to reconstruct the audio heard by the participants using their brainwaves.

First, an AI model looked at the data generated from the brains’ responses to components of the song, like the changes in rhythm, pitch, and tone. Then a second model rejiggered the piecemeal song and estimated the sounds heard by the patients. Of the seven audio samples published in the study results, we think #3 sounds the most like the song. It’s kind of creepy but ultimately very cool. What do you think?

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