Machining With Electricity Explored In The Hack Chat

January 20, 2023 by Tom Nardi 16 Comments

As a Hackaday reader, it’s safe to assume you’ve got a better than average understanding of electricity. There’s also an excellent chance you’re familiar with machining, and may even have a lathe or old mill in the workshop. But combining the two, and actually machining a piece of metal with electricity, isn’t something that many home gamers can boast first-hand experience with.

Of course, that doesn’t mean there isn’t an interest. To help answer the burning (or at least, sparking) questions from the community, CEO and founder of Voxel Innovations Daniel Herrington stopped by this week’s Hack Chat to talk about the cutting edge of both electric discharge machining (EDM) and the closely related field of electrochemical machining (ECM). While his company uses the technology to produce components at incredible scales, Daniel got his start tinkering in the garage like so many of us, enabling him to provide both a professional and hobbyist prospective on the technologies.

Naturally, the first big question to be addressed was the difference between EDM and ECM. Put simply, electric discharge machining uses high-voltage to literally blast away material from the workpiece. The resulting finish is generally rough, and progress through the material tends to be slow, but it’s relatively simple to implement.

In contrast electrochemical machining could be thought of as a sort of reverse electroplating process, as the material being removed from the workpiece is dissolved and transferred to the cathode — though in practice the flow of pressurized electrolyte keeps it from actually plating the negatively charged tool. ECM is a faster process than EDM and allows for an exceptionally smooth surface finish, but is considerably more challenging from a technical perspective. Continue reading “Machining With Electricity Explored In The Hack Chat” →

Hackaday Podcast 202: CNC Monks, Acrobot, Bootleg Merch, And The Rise And Fall Of Megahex

January 20, 2023 by Kristina Panos 1 Comment

This week, Editor-in-Chief Elliot Williams and Assignments Editor Kristina Panos stood around and marveled at machinery in its many forms, from a stone-cutting CNC to an acrobatic robot to an AI-controlled Twitch v-tuber. But before all of that, we took a look at the winners of our FPV Vehicle Contest, poured one out for Google Stadia, and Elliot managed to stump Kristina once again with this week’s What’s That Sound. Will you fare better?

Later, we drooled over an open-source smart watch, argued screen printing versus stenciling when it comes to bootleg Hackaday merch, and got into the finer points of punycodes.

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!

And/or download it and listen offline.

Continue reading “Hackaday Podcast 202: CNC Monks, Acrobot, Bootleg Merch, And The Rise And Fall Of Megahex” →

This Week In Security: Git Deep Dive, Mailchimp, And SPF

January 20, 2023 by Jonathan Bennett 10 Comments

First up, git has been audited. This was an effort sponsored by the Open Source Technology Improvement Fund (OSTIF), a non-profit working to improve the security of Open Source projects. The audit itself was done by researchers from X41 and GitLab, and two critical vulnerabilities were found, both caused by the same bad coding habit — using an int to hold buffer lengths.

On modern systems, a size_t is always unsigned, and the same bit length as the architecture bit-width. This is the proper data type for string and buffer lengths, as it is guaranteed not to overflow when handling lengths up to the maximum addressable memory on the system. On the other hand, an int is usually four bytes long and signed, with a maximum value of 2^31-1, or 2147483647 — about 2 GB. A big buffer, but not an unheard amount of data. Throw something that large at git, and it will break in unexpected ways.

Our first example is CVE-2022-23521, an out of bounds write caused by an int overflowing to negative. A .gitattributes file can be committed to a repository with a modified git client, and then checking out that repository will cause the num_attrs variable to overflow. Push the overflow all the way around to a small negative number, and git will then vastly under-allocate the attributes buffer, and write all that data past the end of the allocated buffer.

CVE-2022-41903 is another signed integer overflow, this time when a pretty print format gets abused to do something unexpected. Take a look at this block of code:

Continue reading “This Week In Security: Git Deep Dive, Mailchimp, And SPF” →

Linux Fu: UEFI Booting

January 19, 2023 by Al Williams 30 Comments

Unless your computer is pretty old, it probably uses UEFI (Unified Extensible Firmware Interface) to boot. The idea is that a bootloader picks up files from an EFI partition and uses them to start your operating system. If you use Windows, you get Windows. If you use Linux, there’s a good chance you’ll use Grub which may or may not show you a menu. The problem with Grub is you have to do a lot of configuration to get it to do different things. Granted, distros like Ubuntu have tools that go through and do much of the work for you and if you are satisfied with that, there’s no harm in using Grub to boot and manage multiple operating systems.

An alternative would be rEFInd, which is a nice modern UEFI boot manager. If you are still booting through normal (legacy) BIOS, the installation might be a hassle. But, in general, rEFInd, once installed, just automatically picks up most things, including Windows, Mac, and Linux operating systems and kernels. The biggest reasons you might change the configuration is if you want to hide some things you don’t care about or change the visual theme.

Continue reading “Linux Fu: UEFI Booting” →

Retro Gadgets: Tired Of The Beatles On 8 Track? Try The Police

January 18, 2023 by Al Williams 48 Comments

In the 1970s, 8-track audio players were very popular, especially in cars. For a couple of bucks, you could have the latest album, and you didn’t have to flip the tape in the middle of a drive like you did with a cassette. We’ve seen plenty of 8-tracks and most of us a certain age have even owned a few players. But we couldn’t find anyone who would admit to owning the Bearcat 8 Track Scanner, as seen in the 1979 Popular Electronics ad below.

Continue reading “Retro Gadgets: Tired Of The Beatles On 8 Track? Try The Police” →

All About USB-C: High-Speed Interfaces

January 17, 2023 by Arya Voronova 40 Comments

One amazing thing about USB-C is its high-speed capabilities. The pinout gives you four high-speed differential pairs and a few more lower-speed pairs, which let you pump giant amounts of data through a connector smaller than a cent coin. Not all devices take advantage of this capability, and they’re not required to – USB-C is designed to be accessible for every portable device under the sun. When you have a device with high-speed needs exposed through USB-C, however, it’s glorious just how much USB-C can give you, and how well it can work.

The ability to get a high-speed interface out of USB-C is called an Alternate Mode, “altmode” for short. The three altmodes you can encounter nowadays are USB3, DisplayPort and Thunderbolt, there’s a few that have faded into obscurity like HDMI and VirtualLink, and some are up and coming like USB4. Most altmodes require digital USB-C communication, using a certain kind of messages over the PD channel. That said, not all of them do – the USB3 is the simplest one. Let’s go through what makes an altmode tick. Continue reading “All About USB-C: High-Speed Interfaces” →

2022 FPV Contest: Congratulations To The Winners!

January 16, 2023 by Elliot Williams 6 Comments

We wanted to see what the Hackaday crowd was up to in first-person view tech, and you didn’t disappoint! Commercial FPV quads have become cheap enough these days that everyone and their mom got one for Christmas, so it was fantastic to see the DIY spirit in these projects. Thanks to everyone who entered.

The Winners

None of the entries do the DIY quite as thoroughly as [JP Gleyzes]’s “poor man’s FPV journey”. This is actually three hacks in one, with DIY FPV goggles made from cheap optics and 3D printed additions, a USB joystick to PPM adapter to use arbitrary controllers with an RC transmitter, and even a fully DIY Bluetooth-based controller for a popular flight simulator. [JP] has done everything but build his own drone, and all the files are there for you to use, whether you’re goal is to do it on the cheap, or to do something new.

If you want to build your own drone from scratch, though, ESP32 Drone project has you covered. At least, mostly. This build isn’t entirely finished yet, and it’s definitely got some crash-testing still in its future, but the scope and accessibility of the project is what caught our eyes. The goal is to make a lightweight indoor quad around parts we can all get easily and cheaply, completely scratch-built. This drone is meant to be controlled by a smartphone, and the coolest parts for us are the ESP_Drone and ESPStream software that run on the drone and your phone respectively. Congrats to [Jon VB]! Now get that thing in the air.

And if you’re looking for a tidy little build, [Tobias]’s Mini FPV Speed Tank doesn’t disappoint. It’s a palm-sized mini tank, but this thing hauls, and looks like a ton of fun to drive around. It uses an absolutely tiny RP2040 module, an equally tiny receiver, and a nano FPV camera and transmitter to keep it compact. The 3D-printed frame and tracks are so nice that we’re not even complaining that the FPV rig is simply rubber-banded on top of the battery. This looks like a super fun build.

Each of these three projects have won a $150 Digi-Key shopping spree to help out with parts in this, or your next project. Thanks again to Digi-Key for sponsoring!

Continue reading “2022 FPV Contest: Congratulations To The Winners!” →