New Years Circuit Challenge: Make This RFID Circuit

December 31, 2024 by Jenny List 9 Comments

A 125kHz PCB antenna, a spiral pattern on a PCB. — The Proxmark3 PCB 125kHz antenna., GNU GPL version 2, GitHub link.

Picture this: It’s the end of the year, and a few hardy souls gather in a hackerspace to enjoy a bit of seasonal food and hang out. Conversation turns to the Flipper Zero, and aspects of its design, and one of the parts we end up talking about is its built-in 125 kHz RFID reader.

It’s a surprisingly complex circuit with a lot of filter components and a mild mystery surrounding the use of a GPIO to pulse the receive side of its detector through a capacitor. One thing led to another as we figured out how it worked, and as part of the jolity we ended up with one member making a simple RFID reader on the bench.

Just a signal generator making a 125 kHz square wave, coupled to a two transistor buffer pumping a tuned circuit. The tuned circuit is the coil scavenged from an old RFID card, and the capacitor is picked for resonance in roughly the right place. We were rewarded with the serial bitstream overlaying the carrier on our ‘scope, and had we added a filter and a comparator we could have resolved it with a microcontroller. My apologies, probably due to a few festive beers I failed to capture a picture of this momentous event. Continue reading “New Years Circuit Challenge: Make This RFID Circuit” →

When The EU Speaks, Everyone Charges The Same Way

December 30, 2024 by Jenny List 98 Comments

The moment everyone has been talking about for years has finally arrived, the European Union’s mandating of USB charging on all portable electronic devices is now in force. While it does not extend beyond Europe, it means that there is a de facto abandonment of proprietary chargers in other territories too. It applies to all mobile phones, tablets, digital cameras, headphones, headsets, game consoles, portable speakers, e-readers, keyboards, mice, portable navigation systems and earbuds, and from early 2026 it will be extended to laptops.

Hackaday readers will probably not need persuading as to the benefits of a unified charger, and truth be told, there will be very few devices that haven’t made the change already. But perhaps there’s something more interesting at work here, for this moment seals the place of USB-C as a DC power connector rather than as a data connector that can also deliver power.

Back in 2016 we lamented the parlous state of low voltage DC power standards, and in the time since then we’ve arrived at a standard involving ubiquitous and commoditised power supplies, cables, and modules which we can use for almost any reasonable power requirement. You can thank the EU for that mobile phone now having the same socket as its competitor, but you can thank the USB Implementers Forum for making DC power much simpler.

Release Your Inner Ansel Adams With The Shitty Camera Challenge

December 30, 2024 by Jenny List 22 Comments

Social media microblogging has brought us many annoying things, but some of the good things that have come to us through its seductive scrolling are those ad-hoc interest based communities which congregate around a hashtag. There’s one which has entranced me over the past few years which I’d like to share with you; the Shitty Camera Challenge. The premise is simple: take photographs with a shitty camera, and share them online. The promise meanwhile is to free photography from kit acquisition, and instead celebrate the cheap, the awful, the weird, and the wonderful in persuading these photographic nonentities to deliver beautiful pictures.

Where’s The Hack In Taking A Photo?

Of course, we can already hear you asking where the hack is in taking a photo. And you’d be right, because any fool can buy a disposable camera and press the shutter a few times. But from a hardware hacker perspective this exposes the true art of camera hacking, because not all shitty cameras can produce pictures without some work.

The #ShittyCameraChallenge has a list of cameras likely to be considered shitty enough, they include disposables, focus free cameras, instant cameras, and the cheap plastic cameras such as Lomo or Holga. But also on the list are models which use dead film formats, and less capable digital cameras. It’s a very subjective definition, and thus in our field everything from a Game Boy camera or a Raspberry Pi camera module to a home-made medium format camera could be considered shitty. Ans since even the ready-made shitty cameras are usually cheap and unloved second-hand, there’s a whole field of camera repair and hacking that opens up. Finally, here’s a photography competition that’s fairly and squarely on the bench of Hackaday readers. Continue reading “Release Your Inner Ansel Adams With The Shitty Camera Challenge” →

A Mechanical Calculator For The Modern Age

December 26, 2024 by Jenny List 16 Comments

There was a brief period through the 1960s into the 1970s when the last word in electronics was the calculator. New models sold for hundreds of dollars, and owning one made you very special indeed. Then the price of the integrated circuit at their heart fell to the point at which anyone could afford one, and a new generation of microcomputers stole their novelty for ever. But these machines were by no means the first calculators, and [What Will Makes] shows us in detail the workings of a mechanical calculator.

His machine is beautifully made with gears hand-cut from plywood, and follows a decimal design in which the rotation of a gear with ten teeth represents the numbers 0 to 9. We’re taken through the mechanical processes behind addition, subtraction, multiplication, and division, showing us such intricacies as the carry lever or a sliding display mechanism to implement a decimal equivalent of a bitwise shift multiplication.

We have to admit to be particularly impressed by the quality of the work, more so because these gears are hand made. To get such a complex assembly to work smoothly requires close attention to tolerance, easy with a laser cutter but difficult by hand. We heartily recommend watching the video, which we’ve placed below the break.

Meanwhile if you’d like more mechanical calculators, take a look at one of the final generation of commercial models.

Continue reading “A Mechanical Calculator For The Modern Age” →

OpenWRT, But On An Unsupported Router

December 26, 2024 by Jenny List 15 Comments

Everyone likes something cheap, and when that cheap thing is a router that’s supported by OpenWRT, it sounds like a win. [Hennung Paul] ordered a Wavlink WL-WN586X3 for the princely sum of 39 Euros, but was disappointed to find his device a rev. 2 board rather than the rev.1 board supported by the Linux distribution. Toss it on the failed projects pile and move on? Not at all, he hacked together a working OpenWRT for the device.

It’s fair to say that a majority of Hackaday readers will have familiarity with Linux, but that’s something which runs on a sliding scale from “Uses Ubuntu a bit” all the way to “Is at one with the kernel”. We’d rate ourselves somewhere around halfway along that scale in terms of having an in-depth knowledge of userland and a working knowledge of some of the internals which make the operating system tick even if we’re apprehensive about tinkering at that level. [Henning] has no such limitations, and proceeds to take the manufacturer’s distribution, itself a heavily modified OpenWRT, and make it his own. Booting over tFTP we’re used to, and we’re particularly impressed to see him using a Raspberry Pi as a surrogate host for the desoldered Flash chip over SPI.

It’s a long path he takes to get the thing working and we’re not sure we could follow it all, but we hope that the result will be a new device added to OpenWRT’s already extensive support list. It’s sometimes a shock to find this distro is now over two decades old.

When It Comes To DOS, Don’t Forget DR-DOS.

December 25, 2024 by Jenny List 44 Comments

Despite the latest and greatest Intel-derived computers having multi-core 64-bit processors and unimaginably fast peripherals, at heart they all still retain a compatibility that goes back to the original 8086. This means that they can, in theory at least, still run MS-DOS. The venerable Microsoft 16-bit OS may now be long discontinued, but there is still enough need for DOS that the open-source FreeDOS remains in active development. The Register are here to remind us that there’s another open-source DOS on the block, and that it has a surprising history.

SvarDOS is an open source DOS distribution, and it’s interesting because it uses a derivative of the DR-DOS kernel, an OS which traces its roots back to Digital Research’s CP/M operating system of the 1970s. This found its way briefly into the open source domain courtesy of the notorious Caldera Inc back in the 1990s, and has continued to receive some development effort ever since. As the Reg notes, it has something FreeDOS lacks, the ability to run Windows 3.1 should you ever feel the need. They take it for a spin in the linked article, should you be curious.

It’s something which has surprised us over the years, that aside from the world of retrocomputing we still occasionally find FreeDOS being distributed, usually alongside some kind of hardware maintenance software. Even four decades or more later, it’s still of value to have the simplest of PC operating systems to hand.

It’s worth pointing out that there’s a third open-source DOS in the wild, as back in April Microsoft released MS-DOS version 4 source code. But as anyone who used it will tell you, that version was hardly the pick of the bunch.

Header: Ivan Radic, CC BY 2.0.

A Pi Pico Makes A Spectrum Laptop

December 23, 2024 by Jenny List 9 Comments

There are many retrocomputer emulation projects out there, and given the relative fragility of the original machines as they enter their fifth decade, emulation seems to be the most common way to play 8-bit games. It’s easy enough to load one on your modern computer, but there are plenty of hardware options, too. “The computer we’d have done anything for back in 1983” seems to be a phrase many of them bring to mind, but it’s so appropriate because they keep getting better. Take [Stormbytes1970]’s Pi Pico-powered Sinclair ZX Spectrum mini laptop (Spanish language, Google Translate link), for example. It’s a slightly chunky netbook that’s a ZX Spectrum, and it has a far better keyboard than the original.

On the PCB is the Pico, the power supply circuitry, an SD card, and a speaker. But it’s when the board is flipped over that the interesting stuff starts. In place of the squidgy rubber keyboard of yore, it has a proper keyboard,. We’re not entirely sure which switch it uses, but it appears to be a decent one, nevertheless. The enclosure is a slick 3D-printed sub-netbook for retro gaming on the go. Sadly, it won’t edit Hackaday, so we won’t be slipping one in the pack next time we go on the road, but we like it a lot.

Continue reading “A Pi Pico Makes A Spectrum Laptop” →