Bad To The Bluetooth: You Shouldn’t Use This Jammer

August 21, 2025 by Jenny List 12 Comments

Back in the day, an FM bug was a handy way to make someone’s annoying radio go away, particularly if it could be induced to feedback. But these days you’re far more likely to hear somebody’s Bluetooth device blasting than you are an unruly FM radio.

To combat this aural menace, [Tixlegeek] is here with a jammer for the 2.4 GHz spectrum to make annoying Bluetooth devices go silent. While it’s not entirely effective, it’s still of interest for its unashamed jankiness. Besides, you really shouldn’t be using one of these anyway, so it doesn’t really matter how well it works.

Raiding the AliExpress 2.4 GHz parts bin, there’s a set of NRF24L01+ modules that jump around all over the band, a couple of extremely sketchy-looking power amplifiers, and a pair of Yagi antennas. It’s not even remotely legal, and we particularly like the sentence “After running the numbers, I realized it would be cheaper and far more effective to just throw a rock at [the Bluetooth speaker]“. If there’s a lesson here, perhaps it is that effective jamming comes in disrupting the information flow rather than drowning it out.

This project may be illegal, but unlike some others we think it (probably) won’t kill you.

The PC In Your Pico

August 18, 2025 by Jenny List 34 Comments

We’re all used to emulating older computers here, and we’ve seen plenty of projects that take a cheap microcontroller and use it to emulate a classic home computer or gaming platform. They’re fun, but serve mostly as a way to relive old toys.

As microcontrollers become faster though it’s inevitable that the machines they can emulate become more powerful too, so we’re moving into the realm of emulating productivity machines from years past. An example is [Ilya Maslennikov]’s pico-286, which as its name suggests, is a 286 PC emulator for the Raspberry Pi Pico.

It has an impressive set of sound and video card emulations, can drive either a VGA or an HDMI monitor, and uses a PS/2 keyboard and mouse. If DOS games are your thing it should provide what you want, but it’s caught our eye because there was a time when a 286 DOS PC was a productivity machine. There’s a huge library of still-useful software for DOS, and thus the prospect of a handheld DOS PC still has some appeal. We’d love to see someone put this in a badge.

MS-DOS may no longer be for sale, but there are several ways to land an open-source DOS in 2025. FreeDOS is something of a powerhouse.

It’s A Pi, But It’s Not Quite A Raspberry Pi

August 17, 2025 by Jenny List 17 Comments

When is a Raspberry Pi not a Raspberry Pi? Perhaps when it’s a Pi Pico-shaped board with an RP3A0 SoC from a Raspberry Pi Zero 2, made by [jonny12375].

Back in the early days of the Raspberry Pi, there was a offering from the Korean manufacturer Odroid, which wasn’t merely a similar machine with a different SoC, but a full clone in a smaller form factor featuring the same BCM2385 chip as the original. It was electrically and software-wise identically to the real thing, which we suspect didn’t go down very well with the Pi folks in Cambridge. The supply of Broadcom chips dried up, and ever since then the only way to get a real Pi has been from the official source. That’s not quite the end of the unofficial Pi story though, because a few hardy experimenters have made Pi clones like this one using chips desoldered from the real thing.

It’s the fruit of a reverse-engineering project to find the chip’s pinout, and it’s a proof of concept board rather than the intended final target of the work. The process involved painstakingly sanding down each layer of a Zero 2 board to reveal the traces and vias. The current board has a few quirks but it boots, making this an impressive piece of work on all counts. We’re looking forward to seeing whatever the final project will be.

If you’re hungry for more Pi-derived goodness, we’ve also seen one using the part form a Pi 3.

The WHY 2025 Badge And Its 18650s

August 12, 2025 by Jenny List 38 Comments

The largest European hacker camp this year was in the Netherlands — What Hackers Yearn (WHY) 2025 is the latest in the long-running series of four-yearly events from that country, and 2025 saw a move from the Flevoland site used by SHA2017 and MCH2021, back to just north of Alkmaar in Noord-Holland, where the OHM2013 event took place. WHY has found itself making the news in the Dutch technical media for all the wrong reasons over the last few days, after serious concerns were raised about the fire safety of its badge.

The cell supplied with a WHY 2025 badge, with very clear fire safety warning — This is the cell supplied with the WHY badge, complete with manufacturer’s warning.

The concerns were raised from the RevSpace hackerspace in Leidschendam, and centre around the design of the battery power traces on the PCB between the battery holders and the power supply circuitry. Because the 18650 cells supplied with that badge lack any protection circuitry, bridging the power traces could be a fire risk.

In short: their report names the cell holders as having tags too large for their pads on the PCB, a too-tight gap between positive and negative battery traces, protected only by soldermask, and the inadequacy of the badge’s short circuit protection. In the event that metal shorted these battery tags, or wore through the soldermask, the batteries would be effectively shorted, and traces or components could get dangerously hot.

The WHY organizers have responded with a printed disclaimer leaflet warning against misuse of the cells, and added a last-minute epoxy coating to the boards to offer additional protection. Some people are 3D-printing cases, which should also help reduce the risk of short-circuiting due to foreign metal objects. Using an external powerbank with short-circuit protection instead of the cells would solve the problem as well. Meanwhile a group of hackers collecting aid for Ukraine are accepting the batteries as donations.

It’s understood that sometimes bugs find their way into any project, and in that an event badge is no exception. In this particular case, the original Dutch badge team resigned en masse at the start of the year following a disagreement with the WHY2025 organizers, so this badge has been a particularly hurried production. Either way, we are fortunate that the issue was spotted, and conference organizers took action before any regrettable incidents occurred.

End Of The Eternal September, As AOL Discontinues Dial-Up

August 11, 2025 by Jenny List 38 Comments

If you used the internet at home a couple of decades or more ago, you’ll know the characteristic sound of a modem connecting to its dial-up server. That noise is a thing of the past, as we long ago moved to fibre, DSL, or wireless providers that are always on. It’s a surprise then to read that AOL are discontinuing their dial-up service at the end of September this year, in part for the reminder that AOL are still a thing, and for the surprise that in 2025 they still operate a dial-up service.

There was a brief period in which instead of going online via the internet itself, the masses were offered online services through walled gardens of corporate content. Companies such as AOL and Compuserve bombarded consumers with floppies and CD-ROMs containing their software, and even Microsoft dipped a toe in the market with the original MSN service before famously pivoting the whole organisation in favour of the internet in mid 1995. Compuserve was absorbed by AOL, which morphed into the most popular consumer dial-up ISP over the rest of that decade. The dotcom boom saw them snapped up for an exorbitant price by Time Warner, only for the expected bonanza to never arrive, and by 2023 the AOL name was dropped from the parent company’s letterhead. Over the next decade it dwindled into something of an irrelevance, and is now owned by Yahoo! as a content and email portal. This dial-up service seems to have been the last gasp of its role as an ISP.

So the eternal September, so-called because the arrival of AOL users on Usenet felt like an everlasting version of the moment a fresh cadre of undergrads arrived in September, may at least in an AOL sense, finally be over. If you’re one of the estimated 0.2% of Americans still using a dial-up connection don’t despair, because there are a few other ISPs still (just) serving your needs.

The Kilopixel Display

August 9, 2025 by Jenny List 7 Comments

Despite the availability of ready-made displays never being better, there are still some hardy experimenters who take on the challenge of making their own. In [Ben Holmen]’s case the display he built is somewhat unusual and not the most practical, but for us a giant-sized wooden kilopixel display is exactly what the world needs.

It’s a kilopixel display because it has a resolution of 40 by 25 pixels, and it takes the form of a rack of wooden cubes, each of which can be turned by a tool on a gantry to expose either a black or a white side. It’s very slow indeed — he has an over nine hour long video of it in operation — but it is an effective device.

His write-up goes into great detail about the steps taken in its design, starting with spherical pixels rotated by a LEGO wheel and progressing to cubes poked at their corner to rotate. The pusher in this case is a hot glue stick, for the required flexibility. For practicality we’re reminded of this serial oil-and-water display.

The whole thing is online, and if you want you can submit your own images for it to draw. Whether a Wrencher in 25 pixel resolution has enough detail, we’ll leave to you.

2025 One Hertz Challenge: Square Waves The Way You Want ‘Em

August 6, 2025 by Jenny List 8 Comments

On an old fashioned bench a signal generator was once an indispensable instrument, but has now largely been supplanted by the more versatile function generator. Sometimes there’s a less demanding need for a clock signal though, and one way that might be served comes from [Rupin Chheda]’s square wave generator. It’s a small PCB designed to sit at the end of a breadboard and provide handy access to a range of clocks.

On the board is a crystal oscillator running at the usual digital clock frequency of 32.768 kHz, and a CMOS divider chain. This provides frequencies from 2048 Hz down to 0.5 Hz for good measure. It’s a simple but oh-so-useful board, and we can imagine more than a few of you finding space for it on your own benches.

This project is part of our awesome 2025 One Hertz Challenge, celebrating all the things which strut their stuff once a second. It’s by no means the first to feature a 32.768 kHz divider chain, and if you have a similar project there’s still time to enter.