Plenty Of LEDs And Useful Too: The 2025 DORS/CLUC Badge

It’s always nice to see new developments in the world of electronic badges, and while there are events and badge teams pushing the technological envelope there’s still plenty of scope for innovation without too many exotic parts. This year’s DORS/CLUC open source conference in Croatia has just such a badge, with a large alphanumeric LED display as well as USB and an NFC reader. During the conference it displayed the user’s name and could be used in an NFC-based game, but it’s also designed to be used as a general purpose notification device afterwards.

The write-up is familiar to anyone who has been involved with badge production, a tale of long soldering sessions as missing components had to be added later, and of last minute firmware flashing. The heart of the machine is an STM32L073, with an IS31FL3731 LED matrix driver chip and an ST25R3916 for the NFC. All the files can be found in a GitLab repo, and there’s a video below the break showing it all in action.

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2025 Pet Hacks Contest: Keep The Prey At Bay With The Cat Valve

Some cats are what you might call indoor cats, happy to stretch out in the lap of indoor luxury and never bother themselves with the inclement outdoors again. Others however are fully in touch with their Inner Cat, and venture forth frequently in search of whatever prey they can find.

[Rkramer] has a cat of this nature,sadly one with a propensity for returning with live prey. To avoid this problem a solution is called for, and it comes in the shape of the Cat Valve, an automated cat door which enforces a buffer zone in their cellar to prevent unwanted gifts.

It’s a simple enough idea, when an IR sensor connected to a Raspberry Pi 4 detects the cat heading out into the world through the exterior cat flap, the computer fires up a motor connected to a lead screw which closes the flap between buffer zone and house. The cat then has the safety of the buffer zone, but can’t bring the prey fully inside.

If you’re a cat lover you’ll forgive them anything, but we have to admit to being on [Rkramer]’s side with this one. A useful way to keep the prey at bay is something we could have used a few times in the past, too. This project is part of the 2025 Pet Hacks contest. Done something similar for your cat? Why not make it an entry!

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.
Fytó pet plant

2025 Pet Hacks Contest: Fytó – Turn Your Plant Into A Pet

This entry into the 2025 Pet Hacks Contest is about bringing some fun feedback to normally silent plants. Fytó integrates sensors and displays into a 3D printed planter. The sensors read the various environmental and soil conditions that the plant is experiencing, and give you feedback about them via a series of playful expressive faces that are displayed on the screen embedded in the planter.

At the core of the Fytó is a Raspberry Pi Zero 2 W, which has plenty of power to display the animations while also being small enough to easily fit inside the planter without it growing in size much more than a normal planter would be. The sensors include a capacitive soil moisture sensor, a temperature sensor, and a light-dependent resistor. These sensors all provide analog outputs to relay their measurements and so there was an ADS1115 analog-to-digital converter board also included as the Raspberry Pi doesn’t have the required analog pins to communicate with them.

The fun animated faces are displayed with a 2-inch LCD display embedded in the planter. A small acrylic cover is placed in front of the LCD to help ease the transition from the printed planter to the internally mounted screen. The temperature and light sensors were also placed in openings around the planter to ensure they could get good environmental readings. There are six expressions the Fytó can express based on its sensor readings, ranging from happy when all the readings are in a good zone, to thirsty if it needs water or freezing when it’s too cold. Be sure to check out the other entries in the 2025 Pet Hacks Contest.

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2025 Pet Hacks Contest: A Barrel Of Fun For Your Dog

If you ask someone for a piece of received opinion about Bernese mountain dogs, the chances are that the tale of their carrying barrels of brandy round their necks for the revival of those lost in the snow. It’s a story of uncertain provenance and may indeed be a myth, but that hasn’t stopped [Saren Tasciyan] 3D printing one for their faithful hound. In its own way it too is a saviour, for as well as a small camera, it carries a supply of dog poop bags.

It’s a two part print, held together with strong magnets. Waterproofing is achieved using liberal quantities of hot glue. There’s a protrusion on one side designed to take an action camera for a dog’s-eye-view of the world. The files are downloadable, so your pooch can have one too if you like. We are wondering whether a couple of miniatures of brandy might just fit in there as well.

It’s is part of the 2025 Pet Hacks contest, so if this has whetted your appetite, expect more. If your dog carries around something you’ve made, how about making it an entry of your own?

2025 Pet Hacks Contest: A Water Fountain For Your Cat

Part of the charm of having a cat in your life is that by their nature these animals are very interactive. They will tell you in no uncertain terms when something in their lives needs attention, for example when their water dish is empty. But why not give them a drinking fountain all of their own? It’s what [supermarioprof] did for their adorable ginger cat [Piki Piki], providing a cat-operated trickle of water on demand.

It’s a simple enough device in its operation, but very well constructed. There’s a small basin with a drain, and a water cistern valve operated by the cat placing a paw on a lever. This starts a trickle of water, from which they can lap as much as they like.

The physical construction comes courtesy of some laser-cut ply, and what looks like some 3D print work. It’s certainly easy to operate for the cat, and has worked reliably for a few years now.

This project is part of the 2025 Pet Hacks contest, so expect to see more in the same vein. If your cat’s life is improved by one of your projects, consider making an entry yourself!

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Hackaday Links: May 25, 2025

Have you heard that author Andy Weir has a new book coming out? Very exciting, we know, and according to a syndicated reading list for Summer 2025, it’s called The Last Algorithm, and it’s a tale of a programmer who discovers a dark and dangerous secret about artificial intelligence. If that seems a little out of sync with his usual space-hacking fare such as The Martian and Project Hail Mary, that’s because the book doesn’t exist, and neither do most of the other books on the list.

The list was published in a 64-page supplement that ran in major US newspapers like the Chicago Sun-Times and the Philadelphia Inquirer. The feature listed fifteen must-read books, only five of which exist, and it’s no surprise that AI is to behind the muck-up. Writer Marco Buscaglia took the blame, saying that he used an LLM to produce the list without checking the results. Nobody else in the editorial chain appears to have reviewed the list either, resulting in the hallucination getting published. Readers are understandably upset about this, but for our part, we’re just bummed that Andy doesn’t have a new book coming out.

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