Adding Cellular Connectivity To The Hackaday Supercon Badge

December 2, 2023 by Lewin Day 1 Comment

Did you manage to make it down to Hackaday Supercon 2023? Maybe you did, and maybe you had a great time hacking away on the badge. [Dan] and ex-Hackaday alumnus [Mike Szczys] certainly did, with the guys from Golioth adding cellular connectivity to the hardware and developing a community art project.

The badge was hooked up over I2C to a Golioth Aludel Mini, which is a prototyping platform featuring a Sparkfun nRF9160 cellular modem. A custom Micropython implementation was compiled for the badge so that the badge could act as an I2C peripheral to be queried by the Aludel Mini. The sketch app on the badge was tweaked to allow the small pictures it created to be be uploaded to a cloud site called Badgecase, programmed in Rust. Amusingly, it turns out the sketch app uses a rectangular workspace, though you only see a circular section of it on the Supercon badge’s awesomely round display.

Much of the hack is happening off-board from the badge itself, but it’s a neat piece of work that shows how easy cellular connectivity is to implement these days. We’ve seen some other great feats with the Vectorscope badge, and it looked great if you happened to 3D print a case for it, too. Video after the break.

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Honey, I Ate The Camera

December 2, 2023 by Jenny List 17 Comments

We like cameras here at Hackaday. We like them a lot. But until now that liking has never extended to liking their taste. A build from [Dmitri Tcherbadji] could change all that though, and he’s created a working Fuji Instax Square camera made from gingerbread.

To look at, it’s a straightforward box camera, albeit one made from sheets of gingerbread stuck together with what looks like icing. The film rests in an off-the-shelf development unit but the rest is edible, including unexpectedly the lens which is made of sugar glass. The photos it returns are definitely somewhat cloudy, but that it works at all is a significant feat.

While it’s an unconventional choice it’s clear that gingerbread, or at least a baked material similar to it, could become a useful tool in a maker’s arsenal. In this case it’s light-proof, but were instantly curious about how well a moulded piece of dough might hold its shape when baked. He reports the gingerbread expanding in the oven, however we’re guessing that tuning the quantity of raising agent could help.

Home-made cameras have featured here many times, but Instax seems to pop up most often as a hacked in replacement for obsolete Polaroid packs.

Mozilla Lets Folks Turn AI LLMs Into Single-File Executables

December 2, 2023 by Donald Papp 19 Comments

LLMs (Large Language Models) for local use are usually distributed as a set of weights in a multi-gigabyte file. These cannot be directly used on their own, which generally makes them harder to distribute and run compared to other software. A given model can also have undergone changes and tweaks, leading to different results if different versions are used.

To help with that, Mozilla’s innovation group have released llamafile, an open source method of turning a set of weights into a single binary that runs on six different OSes (macOS, Windows, Linux, FreeBSD, OpenBSD, and NetBSD) without needing to be installed. This makes it dramatically easier to distribute and run LLMs, as well as ensuring that a particular version of LLM remains consistent and reproducible, forever.

This wouldn’t be possible without the work of [Justine Tunney], creator of Cosmopolitan, a build-once-run-anywhere framework. The other main part is llama.cpp, and we’ve covered why it is such a big deal when it comes to running self-hosted LLMs.

There are some sample binaries available using the Mistral-7B, WizardCoder-Python-13B, and LLaVA 1.5 LLMs. Just keep in mind that if you’re on a Windows platform, only the LLaVA 1.5 will run, because it’s the only one that squeaks under the 4 GB limit on executable files that Windows has. If you run into issues, check out the gotchas list for troubleshooting tips.

Build Yourself A Screw Propelled Robot To Tackle The Dirt

December 2, 2023 by Lewin Day 11 Comments

Wheels and tracks are common choices for robot propulsion, but they’re not the only game in town. You can do some nifty things with long extruded screws , and they work pretty well in soft terrain. [gokux] set about building a small robot using this propulsion method using 3D printed parts.

The build uses a Seeed Studio XIAO ESP32S3 as the brains of the operation. This provides wireless connectivity for remote control, as well as a way to get a low-latency video feed out of the robot from the OV2640 camera. The ESP32 controls a pair of brushed DC gearmotors via a DRV8833 motor driver. Each drives one of the two screws on the robot. By driving the two screws separately, the robot has simple skid steering. Two 18650 lithium-ion cells provide power for the robot, and are charged via a TP4056 battery charger module.

If you want to build a small robot that can handle soft terrain well, screw drives could be just the solution you’re looking for. They’re usually a bit slow, though, especially for human-scale conveyances, so don’t write off wheels or tracks if you don’t have to. And, of course, when your build is done, don’t forget to put it online and tell us all about it!

Update On The BLUFFS Bluetooth Vulnerability

December 2, 2023 by Maya Posch 13 Comments

As we first reported in yesterday’s weekly security post, researchers at EURECOM have revealed the details (PDF, references) of a new man-in-the-middle (MITM) attack on Bluetooth 4.2 through 5.4, which has been assigned CVE-2023-24023. Like preceding CVEs, it concerns the session authentication between Bluetooth devices, where the attacker uses spoofed paired or bonded devices to force the use of a much shorter encryption key length.

The name of this newly discovered vulnerability is BLUFFS (Bluetooth Forward and Future Secrecy), where forward and future secrecy are important terms that refer to the protection of secure sessions against compromise in the past (forward, FoS) and future (FuS). The CVE presentation notes that the Bluetooth specification does not cover either FuS or FoS. In total two new architectural vulnerabilities were discovered, both of which attack the security key.

The Bluetooth SIG has released a statement regarding this attack method. Although serious, it would seem that the core issue is that some implementations allow for encryption key lengths below 7 octets:

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The Physics Lesson I Keep Re-Learning

December 2, 2023 by Elliot Williams 69 Comments

One of the most broadly applicable ideas I’ve ever encountered is the concept of impedance matching. If you’re into radio frequency electronics, you’re probably thinking that I mean getting all your circuit elements working to a common characteristic resistance for maximum power transfer. (If you’re not, you’re probably wondering what that jumble of words even means. Fear not!)

But I mean impedance matching in the larger sense. Think about driving a stick-shift automobile. In low gear, the engine has a lot of torque on the wheels, but it can’t spin them all that fast. In high, the wheels turn fastest, but there’s not enough torque to get you started from a standstill. Sometimes you need more force and less motion, other times more motion and less force. The gearbox lets you match the motor’s power to the resistance – the impedance – it’s trying to overcome.

Or think about a cello. The strings are tight, and vibrate with quite a bit of force, but they don’t move all that much. Air, which is destined to carry the sound to your ear, doesn’t take much force to move, and the cello would play louder if it moved more of it. So the bridge conveys the small, but strong, vibrations of the strings and pushes against the top of the resonant box that makes up the body of the instrument. This in turn pushes a lot of air, but not very hard. This is also why speakers have cones, and also why your ear has that crazy stirrup mechanism. Indeed, counting the number of impedance matches between Yo Yo Ma and your brain, I come up with four or five, including electrical matches in the pre-amp.

I mention this because I recently ran into a mismatch. Fans blow air either hard or in large volume. If you pick a fan that’s designed for volume, and put it in a pressure application, it’s like trying to start driving in fifth gear. It stalled, and almost no air got pushed up through the beans in my new “improved” coffee roaster, meaning I had to rebuild it with the old fan, and quick before the next cup was due.

I ran into this mismatch even though I knew there was a possible impedance issue there. I simply don’t have a good intuitive feel how much pressure I needed to push the beans around – the impedance in question – and I bought the wrong fan. But still, knowing that there is a trade-off is a good start. I hope this helps you avoid walking in my footsteps!

Generating Motion Via Nitinol Wires

December 2, 2023 by Lewin Day 13 Comments

Generally, when we’re looking to build something that moves we reach for motors, servos, or steppers — which ultimately are all just variations on the same concept. But there are other methods of locomotion available. As [Jamie Matthews] demonstrates, Nitinol wires can be another way to help get things moving.

Nitinol is a type of metal wire made of nickel and titanium that is also known as “memory wire”, because it can remember its former shape and transition back to it with a temperature change. [Jamie] uses this property to create a simple hand that is actuated by pieces of wire sourced from Amazon. This is actually a neat way to go, as it goes some way to mimicking how our own hands are moved by our tendons.

[Jamie] does a great job of explaining how to get started with Nitinol and how it works in a practical sense. We’ve seen it put to some wacky uses before, too, such as the basis for an airless tire.

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