Author: Jenny List

3267 Articles

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

June 1, 2025 by 2 Comments

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.

Continue reading “Plenty Of LEDs And Useful Too: The 2025 DORS/CLUC Badge” →

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

May 30, 2025 by 12 Comments

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 Hackaday Pet Hacks Contest

What Does Linux Need? A Dial!

May 30, 2025 by 12 Comments

It’s fair to say that there can’t be many developers who have found the need for a rotary telephone dial as a peripheral for their Linux computer, but in case you are among them you might find [Stefan Wiehler]’s kernel driver for rotary dials to be of use.

It’s aimed at platforms such as systems-on-chip that have ready access to extra GPIOs, of which it will need a couple to service the BUSY and PULSE lines. There are full set-up instructions, and once it’s in place and configured it presents the dial as though it were a number pad.

We like this project, in fact we like it a lot. Interfacing with a dial is always something we’ve done with a microcontroller though, so it will be interesting to see whether it finds a use beyond merely curiosity. We can already see a generation of old-school dial IP phones using Linux-capable dev boards. He leaves us with a brief not as to whether Linus Torvalds would see it as worthy of mainline inclusion, and sadly however much we want things to be different, we agree that it might be wishful thinking.

If you’d like to use a dial phone, there can be simpler ways to do it.

Header: Billy Brown, CC BY 2.0 .

Bring Back The BIOS! (To UEFI Systems, That Is)

May 29, 2025 by 22 Comments

At the dawn of the PC, IBM provided the Basic Input Output System (BIOS). It took care of bringing the machine up, and exposed a series of software hooks for the hardware. Over the years the BIOS and its updated descendants served us well, but as we entered a 64-bit world its limitations began to show.

The replacement was the Unified Extensible Firmware Interface or UEFI, and the chances are you’re viewing this on a machine which uses it in some capacity. But what if you only have UEFI and need BIOS to run a piece of older software? Never fear, because here’s CSMWrap, which brings it back, just for you.

Under the hood it’s a wrapper for the SeaBIOS compatibility support module, doing the work of setting up the memory mapping such that it will load, and ensuring that other services such as the VGA BIOS are loaded. As it stands it can boot FreeDOS and some older Windows versions under UEFI in QEMU, and it’s claimed also run on real hardware. We don’t often need to run DOS on our 2025 machine, but it’s neat to know we can.

Meanwhile if the BIOS interests you, know that there’s also an open source BIOS for the earliest of PCs.

BIOS header image: Thomas Schanz, CC BY-SA 4.0.

Bubble Displays Make A Neat Retro Clock

May 28, 2025 by 6 Comments

In 2025 we are spoiled for choice when it comes to displays, with affordable LCDs, OLEDs, TFTs, and e-ink panels of all sizes only a few clicks away. But in decades past, such exotica were not on the menu for casual construction. Instead there were a range of LED seven segment displays which have now largely passed out of use.

Among them were HP’s bubble displays, assemblies of miniature LEDs on a PCB, topped with plastic bubble lenses. If you had a calculator in the 1970s it probably had one, but in the present, [Joshua Coleman] has incorporated one into a pleasingly retro digital clock.

Inside the 3D printed case is an ESP32 with a pair of 74HC595 shift registers to drive the display, and an 18650 battery with all associated charging and protection circuitry. It’s a surprisingly simple circuit, and the code is provided on the page. He makes an apology to non-Americans for his use of US date formats, but we think few readers will be unable to change it to reflect the only date format which really matters.

If you find a bubble display, hang on to it. They’re certainly something we’ve seen before here a few times.

Reconditioning A Vintage CRT Tube

May 27, 2025 by 28 Comments

Plenty of readers will be familiar with CRT televisions, not least because many of us use them with retrocomputers and consoles. But perhaps fewer will have worked with CRTs themselves as components, and of those, fewer still will be familiar with the earlier generation of tubes. In the first few decades of color TV the tubes were so-called delta gun because their three electron guns were arranged in a triangular form. [Colorvac] has put up a video in which they demonstrate the reconditioning of one of these tubes from a late-1960s Nordmende TV.

The tube in question isn’t one of the earlier “roundies” you would find on an American color TV from the ’50s or early ’60s, instead it’s one of the first generation of rectangular (ish) screens. It’s got an under-performing blue gun, so they’re replacing the electron gun assembly. Cutting the neck of the tube, bonding a new neck extension, and sealing in a new gun assembly is not for the faint-hearted, and it’s clear they have both the specialist machinery and the experience required for the job. Finally we see the reconditioned tube put back into the chassis, and are treated to a demonstration of converging the three beams.

For those of us who cut our teeth on these devices, it’s fascinating.

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

May 26, 2025 by 3 Comments

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 Hackaday Pet Hacks Contest