Hackaday Podcast Episode 328: Benchies, Beanies, And Back To The Future

July 11, 2025 by Kristina Panos 1 Comment

This week, Hackaday’s Elliot Williams and Kristina Panos joined forces to bring you the latest news, mystery sound, and of course, a big bunch of hacks from the previous week.

In Hackaday news, the One Hertz Challenge ticks on. You have until Tuesday, August 19th to show us what you’ve got, so head over to Hackaday.IO and get started now! In other news, we’ve just wrapped the call for Supercon proposals, so you can probably expect to see tickets for sale fairly soon.

On What’s That Sound, Kristina actually got this one with some prodding. Congratulations to [Alex] who knew exactly what it was and wins a limited edition Hackaday Podcast t-shirt!

After that, it’s on to the hacks and such, beginning with a ridiculously fast Benchy. We take a look at a bunch of awesome 3D prints a PEZ blaster and a cowbell that rings true. Then we explore chisanbop, which is not actually K-Pop for toddlers, as well as a couple of clocks. Finally, we talk a bit about dithering before taking a look at the top tech of 1985 as shown in Back to the Future (1985).

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 in DRM-free MP3 and savor at your leisure.

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PlayStation Case Mod Hides Gamer Shame

July 11, 2025 by Tyler August 9 Comments

[Zac] of Zac Builds has a shameful secret: he, a fully grown man, plays video games. Shocking, we know, but such people do exist in our society. After being rightfully laughed out of the family living room, [Zac] relocated his indecent activities to his office, but he knew that was not enough. Someone might enter, might see his secret shame: his PlayStation 5. He decided the only solution was to tear the game console apart, and rebuild it inside of his desk.

All sarcasm aside, it’s hard to argue that [Zac]’s handmade wooden desk doesn’t look better than the stock PS5, even if you’re not one of the people who disliked Sony’s styling this generation. The desk also contains his PC, a project we seem to have somehow missed; the two machines live in adjacent drawers.

While aesthetics are a big motivator behind this case mod, [Zac] also takes the time to improve on Sony’s work: the noisy stock fan is replaced by three silent-running Noctua case fans; the easy-to-confuse power and eject buttons are relocated and differentiated; and the Blu-ray drive gets a proper affordance so he’ll never miss the slot again. An NVMe SSD finishes off the upgrades.

Aside from the woodworking to create the drawer, this project relies mostly on 3D printing for custom mounts and baffles to hold the PS5’s parts and direct airflow where it needs to go. This was made much, much easier for [Zac] via the use of a 3D scanner. If you haven’t used one, this project demonstrates how handy they can be — and also some of the limitations, as the structured-light device (a Creality Raptor) had trouble with the shinier parts of the build. Dealing with that trouble still saved [Zac] a lot of time and effort compared to measuring everything.

While we missed [Zac]’s desk build, we’ve seen his work before: everything from a modernized iPod to wooden sound diffusion panels.

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This Week In Security: Bitchat, CitrixBleed Part 2, Opossum, And TSAs

July 11, 2025 by Jonathan Bennett 10 Comments

@jack is back with a weekend project. Yes, that Jack. [Jack Dorsey] spent last weekend learning about Bluetooth meshing, and built Bitchat, a BLE mesh encrypted messaging application. It uses X25519 for key exchange, and AES-GCM for message encryption. [Alex Radocea] took a look at the current state of the project, suspects it was vibe coded, and points out a glaring problem with the cryptography.

So let’s take a quick look at the authentication and encryption layer of Bitchat. The whitepaper is useful, but still leaves out some of the important details, like how the identity key is tied to the encryption keys. The problem here is that it isn’t.

Bitchat has, by necessity, a trust-on-first-use authentication model. There is intentionally no authentication central authority to verify the keys of any given user, and the application hasn’t yet added an out-of-band authentication method, like scanning QR codes. Instead, it has a favorites system, where the user can mark a remote user as a favorite, and the app saves those keys forever. There isn’t necessarily anything wrong with this approach, especially if users understand the limitations.

The other quirk is that Bitchat uses ephemeral keys for each chat session, in an effort to have some forward secrecy. In modern protocols, it’s desirable to have some protection against a single compromised encryption key exposing all the messages in the chain. It appears that Bitchat accomplishes this by generating dedicated encryption keys for each new chat session. But those ephemeral keys aren’t properly verified. In fact, they aren’t verified by a user’s identity key at all!

The attack then, is to send a private message to another user, present the public key of whoever your’re trying to impersonate, and include new ephemeral encryption keys. Even if your target has this remote user marked as a favorite, the new encryption keys are trusted. So the victim thinks this is a conversation with a trusted person, and it’s actually a conversation with an attacker. Not great. Continue reading “This Week In Security: Bitchat, CitrixBleed Part 2, Opossum, And TSAs” →

Photo showing the wire-wrapped version and PCB version of MyCPU side-by-side.

This Homebrew CPU Got Its Start In The 1990s

July 11, 2025 by John Elliot V 4 Comments

[Sylvain Fortin] recently wrote in to tell us about his Homebrew CPU Project, and the story behind this one is truly remarkable.

He began working on this toy CPU back in 1994, over thirty years ago. After learning about the 74LS181 ALU in college he decided to build his own CPU. He made considerable progress back in the 90s and then shelved the project until the pandemic hit when he picked it back up again and started adding some new features. A little later on, a board house approached him with an offer to cover the production cost if he’d like to redo the wire-wrapped project on a PCB. The resulting KiCad files are in the GitHub repository for anyone who wants to play along at home.

The ALU on [Sylvain]’s CPU is a 1-bit ALU which he describes as essentially a selectable gate: OR, XOR, AND, NOT. It requires more clock steps to compute something like an addition, but, he tells us, it’s much more challenging and interesting to manage at the microcode level. On his project page you will find various support software written in C#, such as an op-code assembler and a microcode assembler, among other things.

For debugging [Sylvain] started out with das blinkin LEDs but found them too limiting in short order. He was able to upgrade to a 136 channel Agilent 1670G Benchtop Logic Analyzer which he was fortunate to score for cheap on eBay. You can tell this thing is old from the floppy drive on the front panel but it is rocking 136 channels which is seriously OP.

The PCB version is a great improvement but we were interested in the initial wire-wrapped version too. We asked [Sylvain] for photos of the wire-wrapping and he obliged. There’s just something awesome about a wire-wrapped project, don’t you think? If you’re interested in wire-wrapping check out Wire Wrap 101.

Listen To The Sound Of The Crystals

July 11, 2025 by Jenny List 33 Comments

We’re all used to crystal resonators — they provide pretty accurate frequency references for oscillators with low enough drift for most of our purposes. As the quartz equivalent of a tuning fork, they work by vibrating at their physical resonant frequency, which means that just like a tuning fork, it should be possible to listen to them.

A crystal in the MHz might be difficult to listen to, but for a 32,768 Hz watch crystal it’s possible with a standard microphone and sound card. [SimonArchipoff] has written a piece of software that graphs the frequency of a watch crystal oscillator, to enable small adjustments to be made for timekeeping.

Assuming a microphone and sound card that aren’t too awful, it should be easy enough to listen to the oscillation, so the challenge lies in keeping accurate time. The frequency is compared to the sound card clock which is by no means perfect, but the trick lies in using the operating system clock to calibrate that. This master clock can be measured against online NTP sources, and can thus become a known quantity.

We think of quartz clocks as pretty good, but he points out how little it takes to cause a significant drift over month-scale timings. if your quartz clock’s accuracy is important to you, perhaps you should give it a look. You might need it for your time reference.

Header: Multicherry, CC BY-SA 4.0.

DIY Navigation System Floats This Boat

July 10, 2025 by Seth Mabbott 8 Comments

[Tom] has taken a DIY approach to smart sailing with a Raspberry Pi as the back end to the navigation desk on his catamaran, the SeaHorse. Tucked away neatly in a waterproof box with a silicone gasket, he keeps the single board computer safe from circuit-destroying salt water. Keeping a board sealed up so tightly also means that it can get a little too warm. Because of this he under-clocks the CPU so that it generates less heat. This also has the added benefit of saving on power which is always good when you aren’t connected to the grid for long stretches of time.

A pair of obsolescent phones and a repurposed laptop screen provide display surfaces for his navdesk. With these screens he has weather forecasts, maps, GPS, depth, speed over ground — all the data from all the onboard instruments a sailor could want to stream through a boat’s WiFi network — at his fingertips.

There’s much to be done still. Among other things, he’s added a software defined radio to the Pi to integrate radio monitoring into the system, and he’s started experimenting with reprogramming a buoy transmitter, originally designed for tracking fishing nets, so that it can transmit his boat’s location, speed and heading instead.

The software that ties much of this system together is the open source navigational platform OpenCPN which, with its support for third-party plugins, looks like a great choice for experimenting with new gadgets like fishing net buoy transmitters.

For more nautical computing fun check out this open source shipboard computer, and this data-harvesting, Arduino-driven buoy.

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Double Your Printing Fun With Dual-Light 3D Printing

July 10, 2025 by Al Williams 9 Comments

Using light to 3D print liquid resins is hardly a new idea. But researchers at the University of Texas at Austin want to double down on the idea. Specifically, they use a resin with different physical properties when cured using different wavelengths of light.

Natural constructions like bone and cartilage inspired the researchers. With violet light, the resin cures into a rubbery material. However, ultraviolet light produces a rigid cured material. Many of their test prints are bio-analogs, unsurprisingly.

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