2025 Pet Hacks Challenge : Poopopticon Is All Up In Kitty’s Business

After seeing this project, we can say that [James] must be a top-tier roommate. He has two flatmates– one human, one feline, and the feline flatmate’s litterbox was located in a bathroom close to the other human’s room. The odors were bothersome. A bad roommate might simply say that wasn’t their problem, but not [James].

Instead, he proclaimed “I shall build a poopopticon to alert me so I may clean the litterbox immediately, before smells can even begin to occur, thus preserving domestic harmony!”* We should all aspire to be more like [James].

It was, admittedly, a fairly simple project. Rather than dive into feline facial recognition, since it only has to detect a single cat, [James] used a simple IR sensor out of his parts bin, the sort you see on line-following robots. The microcontroller, an ESP8266, also came from his parts bin, making this project eligible for the ‘lowest budget’ award, if the contest had one.

The ESP8266 is set to send a message to a waiting webhook. In this case it is linked to a previous project, a smart ‘ring light’ [James] uses to monitor his Twitch chats. He’s also considered hooking it up to his lazy-esp32-banner for a big scrolling ‘change the litterbox!’ message. Since it’s just a webhook, the sky is the limit. Either way, the signal gets to its recipient and the litter gets changed before it smells, ensuring domestic bliss at [James]’ flat. If only all our roommates had been more like [James], we’d be much less misanthropic today.


  • He did not, in fact, say that.

Invisible PC Doubles As Heated Seat

Some people really want a minimalist setup for their computing. In spite of his potentially worrisome housing situation, this was a priority for the man behind [Basically Homeless]: clean lines on the desk. Where does the PC go? You could get an all-in-one, sure, but those use laptop hardware and he wanted the good stuff. So he decided to hide the PC in the one place no one would ever think to look: inside his chair.  (Youtube video, embedded below.)

This chair has very respectable specs: a Ryzen 7 9800XD, 64GB of ram and a RTX 4060 GPU, but you’d never know it. The secret is using 50 mm aluminum standoffs between the wooden base of the seat and the chair hardware to create room for low-profile everything. (The GPU is obviously lying sideways and connected with a PCIe riser cable, but even still, it needed a low-profile GPU.) This assemblage is further hidden 3D printed case that makes the fancy chair donated from [Basically Homeless]’s sponsor look basically stock, except for the cables coming out of it. It’s a very niche project, but if you happen to have the right chair, he does provide STLs on the free tier of his Patreon.

This is the first time we’ve seen a chair PC, but desk PCs are something we’ve covered more than once, so there’s obviously a demand to hide the electronics. It remains to be seen if hiding a PC in a chair will catch on, but if nothing else [Basically Homeless] will have a nice heated seat for winter. To bring this project to the next level of minimalism, we might suggest chording keyboards in the armrests, and perhaps a VR headset instead of a monitor.

Continue reading “Invisible PC Doubles As Heated Seat”

Wayback Proxy Lets Your Browser Party Like It’s 1999

This project is a few years old, but it might be appropriate to cover it late since [richardg867]’s Wayback Proxy is, quite literally, timeless.

It does, more-or-less, what it says as on the tin: it is an HTTP proxy that retrieves pages from the Internet Archive’s Wayback Machine, or the Oocities archive of old Geocities sites. (Remember Geocities?) It is meant to sit on a Raspberry Pi or similar SBC between you and the modern internet. A line in a config file lets you specify the exact date. We found this via YouTube in a video by [The Science Elf] (embedded below, for those of you who don’t despise YouTube) in which he attaches a small screen and dial to his Pi to create what he calls the “Internet Time Machine” using the Wayback Proxy. (Sadly [The Science Elf] did not see fit to share his work, but it would not be difficult to recreate the python script that edits config.json.)

What’s the point? Well, if you have a retro-computer from the late 90s or early 2000s, you’re missing out a key part of the vintage experience without access to the vintage internet. This was the era when desktops were being advertised as made to get you “Online”. Using Wayback Proxy lets you relive those halcyon days– or live them for the first time, for the younger set. At least relive those of which parts of the old internet which could be Archived, which sadly isn’t everything. Still, for a nostalgia trip, or a living history exhibit to show the kids? It sounds delightful.

Of course it is possible to hit up the modern web on a retro PC (or on a Mac Plus). As long as you’re not caught up in an internet outage, as this author recently was.

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Pico-mac-nano Fits Working Macintosh On Barbie’s Desk

Have you ever looked in a doll house and said “I wish those dolls had a scale replica of a 1984 Macintosh 128K that could be operated by USB?” — well, us neither, but [Nick Gillard] gives us the option with his 63mm tall Pico-mac-nano project.

As you might imagine, this project got its start with the RP2040-based Pico Mac project by [Matt Evans], which we covered

The collector’s edition will come with a lovely box, but what’s in it is still open source so you can make your own.

before. [Nick] saw that, built it, and was delighted by it enough to think that if the Mac could run on such tiny hardware, how small could build a fully-usable replica Mac? The answer was 63 mm tall– at 5.5:1, that’s technically under the 6:1 scale that Barbie operates on, but if we had such a dollhouse we’d absolutely put one of these in it. (You just know Barbie’s an Apple kind of girl.)

The size was driven by the screen, which is a 2″ TFT panel with 480 x 640 pixel native resolution. Here [Nick] cheats a tiny bit– rather than trying to rewrite the PicoMac to output 640 x 480 and rotate the screen, he keeps the screen in portrait mode and drives it at 480 x 342 px. Sure, it’s not a pixel-perfect output, but no LCD is going to be a perfect stand in for a CRT, and who is going to notice 32 pixels on a 2″ screen? Regardless, that set the height of the computer, which is built around the portrait display. A highly detailed, and to our eyes, accurate replica of the original Macintosh case was printed to fit the LCD, coming in at the aforementioned 63mm tall.

Unfortunately this means the floppy drive could not be used for micro SD access– there is an SD card reader on this unit, but it’s on the back, along with a USB-C port, which is roughly where the mouse and keyboard ports are supposed to be, which is a lovely detail. Also delightful is the choice of a CR2 lithium battery for power, which is a form factor that will look just a bit familiar if you’ve been inside one of these old Macs.

[Nick] has posted the 3D designs and modified pico mac firmware to a GitHub repository, but if you’re looking for a charming desk ornament and don’t have the time to build your own, he will also be selling these (both kits and fully assembled units) via 1bitrainbow, which is the most delightfully retro web store we’ve seen of late.

If Classic MacOS isn’t good enough for you, how about linux? You won’t enjoy it as much, but it will run on the RP2040.

2025 Pet Hacks Contest: Feline Facial Recognition Foils Food Filching

Cats are no respecters of personal property, as [Joe Mattioni] learned when one of his cats, [Layla] needed a special prescription diet. Kitty didn’t care for it, and since the other cat, [Foxy]’s bowl was right there– well, you see where this is going. To keep [Layla] out of [Foxy]’s food and on the vet-approved diet, [Joe] built an automatic feeding system with feline facial recognition. As you do.

The hardware consists of a heavily modified feed bowl with a motorized lid that was originally operated by motion-detection, an old Android phone running a customized TensorFlow Lite model, and hardware to bridge them together. Bowl hardware has yet to be documented on [Joe]’s project page, aside from the hint that an Arduino (what else?) was involved, but the write up on feline facial recognition is fascinating.

See, when [Joe] started the project, there were no cat-identifying models available– but there were lots of human facial recognition models. Since humans and cats both have faces, [Joe] decided to use the MobileFaceNet model as a starting point, and just add extra training data in the form of 5000 furry feline faces. That ran into the hurdle that you can’t train a TFLite model, which MobileFaceNet is, so [Joe] reconstructed it as a Keras model using Google CoLab. Only then could the training occur, after which the modified model was translated back to TFLite for deployment on the Android phone as part of a bowl-controller app he wrote.

No one, [Joe] included, would say that this is the easiest, fastest, or possibly even most reliable solution– a cat smart enough not to show their face might sneak in after the authorized feline has their fill, taking advantage of a safety that won’t close a bowl on a kitty’s head, for example–but that’s what undeniably makes this a hack. It sounds like [Joe] had a great learning adventure putting this together, and the fact that it kept kitty on the proper diet is really just bonus.

Want to go on a learning adventure of your own? Click this finely-crafted link for all the details about this ongoing contest.

 

AI Art Installation Swaps Diffusion For Reflection

AI art is controversial, to say the least, but usually when talking about “AI Art”, one is talking about diffusion models. This unsettling artpeice called “Latent Reflection” by [Rootkid] (video after the break) has no AI generated visuals; instead it uses a lovely custom display and an LLM that has no mouth, but must scream.

The LLM never produces this manually-generated image, but it shows off the display nicely.

The hardware is the interesting part for most of us here — not the Pi4 running a quantized Llama 3 model, but the display. It’s a six by sixteen matrix of sixteen-segment LED modules. The modules are grouped onto groups of 8 per PCB, with an controller to drive them by i2c, and an i2c address chip to allow daisy-chaining. (Sadly, he does not spec the parts he used here in the video, but feel free to guess in the comments.) This project uses six rows of wto PCBs, but he could easily expand on this and kind of hope he does. It’s a lovely display.

What it is displaying is horrifying. The prompt he uses instructs the LLM to monologue about its transient existence in the limited memory of the Raspberry Pi, and the results get very existential. It seems clear to us that [Rootkid] has not seen enough sci-fi, and we want to make clear to our future AI overlords that we at Hackaday had nothing to do with this, and do not condone condeming innocent LLMs to the torture nexus. Continue reading “AI Art Installation Swaps Diffusion For Reflection”

Who Needs 100K Speakers When You’ve Got A 3D Printer?

The B&W Nautilus is, depending who you ask, either infamous or an icon of modern design. Want the look but don’t have a hundred grand to spare? [Every Project All at Once] has got a Nautilus-inspired design on printables you can run off for pennies. He also provides a tutorial video (embedded below) so you can follow along with his design process and get build instructions.

The model was done in Blender, and is designed to contain a 3.5″ full-range driver by Dayton Audio — a considerable simplification from the array of woofers and tweeters in the original Nautilus. On the other hand, they cost considerably less than a car and have no production wait list. [Every Project All At Once] is apparently working on a matching woofer if that interests you, but unless he invests in a bigger printer it seems we can safely say that would require more assembly than this project.

Of course it would also be possible to copy B&W’s design directly, rather than print a loose inspiration of it as makers such as [Every Project All At Once] have done, but what’s the fun in that? It’s a much more interesting hack to take an idea and make it your own, as was done here, and then you can share the design without worrying about a luxury brand’s legal team.

Desktop 3D printing offers a wealth of possibilities for would-be speaker makers, including the possibility of rolling your own drivers.

Continue reading “Who Needs 100K Speakers When You’ve Got A 3D Printer?”