Day: August 5, 2023

Browser-Based Robot Dog Simulator In ~800 Lines Of Code

August 5, 2023 by 9 Comments

[Sergii] has been learning about robot simulation and wrote up a basic simulator for a robodog platform: the Unitree A1. It only took about 800 lines of code to do so, which probably makes it a good place to start if one is headed in a similar direction.

Right now, [Sergii]’s simulator is an interactive physics model than runs in the browser. Software-wise, once the model of the robot exists the Rapier JavaScript physics engine takes care of the physics simulation. The robot’s physical layout comes from the manufacturer’s repository, so it doesn’t need to be created from scratch.

To make the tool useful, the application has two models of the robot, side by side. The one on the left is the control model, and has interactive sliders for limb positions. All movements on the control model are transmitted to the model on the right, which is the simulation model, setting the pose. The simulation model is the one that actually models the physics and gravity of all the desired motions and positions. [Sergii]’s next step is to use the simulator to design and implement a simple walking gait controller, and we look forward to how that turns out.

If Unitree sounds familiar to you, it might be because we recently covered how an unofficial SDK was able to open up some otherwise-unavailable features on the robodogs, so check that out if you want to get a little more out of what you paid for.

Jailbreaking Tesla Infotainment Systems

August 5, 2023 by 22 Comments

With newer cars being computers on wheels, some manufacturers are using software to put features behind a paywall or thwarting DIY repairs. Industrious hackers security researchers have taken it upon themselves to set these features free by hacking a Tesla infotainment system. (via Electrek)

The researchers from TU Berlin found that by using a voltage fault injection attack against the AMD Secure Processor (ASP) at the heart of current Tesla models, they could run arbitrary code on the infotainment system. The hack opens up the double-edged sword of an attacker gaining access to encrypted PII or a shadetree mechanic “extracting a TPM-protected attestation key Tesla uses to authenticate the car. This enables migrating a car’s identity to another car computer without Tesla’s help whatsoever, easing certain repairing efforts.” We can see this being handy for certain other unsanctioned hacks as well.

The attack is purported as being “unpatchable” and giving root access that survives reboots and updates of the system. Since AMD is a vendor to multiple vehicle companies, the question arises as to how widely applicable this hack is to other vehicles suffering from AaaS (Automotive as a Service).

Longing for a modern drivetrain with the simplicity of yesteryear? Read our Minimal Motoring Manifesto.

Making A Kid-Scale Apollo 11 Lunar Lander

August 5, 2023 by 21 Comments

If you’d like to see what goes into making a 1/3-scale Apollo 11 Lunar Module, [Plasanator]’s photos and build details will show off how he constructed one for a kid’s event that was a hit!

The photo gallery gives plenty of ideas about how one would approach a project like this, and readers will surely appreciate the use of an old frying pan as a concrete mold to create the lander’s “feet”. Later, a little paint makes the frying pan become a pseudo-antenna mounted on the lander’s exterior.

Inside, the lander has a control panel with a lot of arcade-style buttons and LED lighting. It’s pretty simple stuff, but livens things up a lot. Bright red lighting for the engine combined with a couple of slow strobe lights really makes it come alive in the dark. The gold foil? Emergency thermal blankets wrapped around the frame.

We happen to have the perfect chaser for this kid-scale lunar module: the Apollo 11 moon landing, recreated with animatronics and LEGO.

Continue reading “Making A Kid-Scale Apollo 11 Lunar Lander” →

LK-99: Diamagnetc Semiconductor, Not Superconductor?

August 5, 2023 by 70 Comments

Every so often, along comes a story which, like [Fox Mulder] with his unexplained phenomena, we want to believe. EM drives and cold fusion for example would be the coolest of the cool if they worked, but sadly they crumbled when subjected to scientific inquiry outside the labs of their originators. The jury’s still out on the latest example, a claimed room-temperature superconductor, but it’s starting to seem that it might instead be a diamagnetic semiconductor.

We covered some of the story surrounding the announcement of LK-99 and subsequent reports of it levitating under magnetic fields, but today’s installment comes courtesy of a team from Beihang University in Beijing. They’ve published a paper in which they characterize their sample of LK-99, and sadly according to them it’s no superconductor.

Instead it’s a diamagnetic semiconductor, something that in itself probably bears some explanation. We’re guessing most readers will be familiar with semiconductors, but diamagnetic substances possess the property of having an external magnetic field induce an internal magnetic field in the opposite direction. This means that they will levitate in a magnetic field, but not due to the Meissner effect, the property of superconductors which causes magnetic field to flow round their outside. The Beijing team have shown by measuring the resistance of the sample that it’s not a superconductor.

So sadly it seems LK-99 isn’t the miracle it was billed as, unless there’s some special quirk in the production of the original Korean sample which didn’t make it to the other teams. We can’t help wondering why a sample from Korea wasn’t subjected to external evaluation rather than leaving the other teams to make their own. Never mind, eh!

DIY Eye Tracking For VR Headsets, From A To Z

August 5, 2023 by 3 Comments

Eye tracking is a useful feature in social virtual reality (VR) spaces because it really enhances presence and communication when one’s avatar has a realistic gaze. Most headsets lack this feature, but EyeTrackVR has a completely open source solution ready for anyone willing to put it together.

Camera is visible in lower right corner.

EyeTrackVR is a combination of hardware, software, and 3D printable mounts for attaching a pair of microcontroller boards, cameras, and IR LEDs to just about any existing VR headset out there. An ESP32-based board and tiny camera module watches each eyeball, and under IR illumination the pupil presents as an easily-identified round black area. Software takes care of turning the camera’s view of the pupil into a gaze direction value that can be plugged into other software.

The project is still under active development, but in its current state is perfectly suitable for creating a functional system that can integrate into a variety of existing headsets with printed mounting brackets. Interested? Check out the intro and if it sounds up your alley, dive into the build guide which spells out everything you need to know. Check out the video below for a demo of EyeTrackVR working in VRChat, along with an overview of software support.

We’ve seen headsets built to custom specs that integrate eye tracking, but even if one is repackaging an existing headset that’s a perfect opportunity to include this feature.

Continue reading “DIY Eye Tracking For VR Headsets, From A To Z” →

Prepare To Brake: Quick Intro To Metal Bending

August 5, 2023 by 9 Comments

If you want to bend metal to make shapes, you might use equipment like a brake. But if you don’t have one, no worries. You can still do a lot with common tools like a vise and torches. [Bwrussell] shows you how. He welds together a die to use as a bending jig and makes a set of table legs.

You might think that putting metal in a vise and bending it isn’t exactly brain surgery. It isn’t, but there is more to it than that. Starting with a bending plan and the creation of the jigs, clamping and bending is only part of it. You can see a little bit of the action in the video below.

Speaking of planning, the design was in Fusion 360’s sheet metal workflow. To facilitate the bends, the build uses two torches. A MAPP torch gets very hot, and a propane torch makes sure that a larger area stays hot. There are quite a few tips you can pick up in this post, even if you aren’t making table legs.

Fusion 360 does a lot of the design work, but if you want a quick lesson on what happens when you bend metal, we can help. Want to make your own metal brake?

Continue reading “Prepare To Brake: Quick Intro To Metal Bending” →

Break Free From Proprietary Digital Radio

August 5, 2023 by 51 Comments

Digital modes are all the rage these days in amateur radio — hams are using protocols like WSPR to check propagation patterns, FT8 to get quick contacts on many bands with relatively low power, and MSK144 to quickly bounce a signal off of a meteor. There’s also digital voice, which has a number of perks over analog including improved audio quality. However, the major downside of most digital voice modes, at least those in use on UHF and VHF, is that they are proprietary with various radio brands having competing digital standards. To get above the noise a more open standard can be used instead.

The M17 standard, originally created by [Wojciech Kaczmarski] aka [SP5WWP], uses Codec 2 to convert voice into a digital format before it is broadcast over the air. Codec 2 is an open standard unlike other audio codecs. M17 also supports reflectors, which can link individual radios or entire repeaters together over the Internet. While you can make purpose-built modules that will interface with most standard radio inputs, it’s also possible to modify existing hardware to support this standard as well. The video below from [Tech Minds] shows this being done to a radio with only a few hardware modifications and the installation of a new firmware.

For anyone who has been frustrated that there’s no real universal standard for digital voice in VHF and above, M17 could be a game-changer if enough people get tired of their friends being on other proprietary digital systems. There’s plenty of supported hardware out there that most hams probably already have already, including a number of TNC devices like the Mobilinkd and the DigiRig, so it shouldn’t be too hard to get started. If you’re more into networking over radio, though, take a look at this method for sending high-bandwidth IP networking over the UHF band. Continue reading “Break Free From Proprietary Digital Radio” →