A Foil Tweeter, Sound From Kitchen Consumables

December 31, 2024 by Jenny List 14 Comments

The world of audio has produced a variety of different loudspeaker designs over the last century, though it’s fair to say that the trusty moving coil reigns supreme. That hasn’t stopped plenty of engineers from trying new ways to make sound though, and [R.U.H] is here with a home-made version of one of them. It’s a foil tweeter, a design in which a corrugated strip of foil is held in a magnetic field, and vibrates when an audio frequency current is passed through it.

He shows a couple of takes on the design, both with neodymium magnets but with different foils and 3D printed or wooden surrounds. They both make a noise when plugged into an amplifier, and unsurprisingly the thicker foil has less of the high notes.

We can see that in there is the possibility for a high quality tweeter, but we can’t help having one concern. This device has an extremely low impedance compared to the amplifier, and thus would probably be drawing far too much current. We’d expect it to be driven through a transformer instead, if he had any care for not killing the amplifier.

Happily there are other uses for a ribbon, they are far better known as microphones.

Continue reading “A Foil Tweeter, Sound From Kitchen Consumables” →

Why 2025 Will Not Be The Year Of Linux On The Desktop

December 31, 2024 by Jenny List 122 Comments

One of the longest running jokes in our sphere is that the coming year will finally be the year of “Linux on the Desktop.” Never mind that the erosion of the traditional Windows-style desktop form of computing is a thing, or that Linux-derived operating systems such as Android or Chrome OS are running on literally billions of devices across the globe, it sends up the unreasonable optimism of Linux enthusiasts back in the day that their nascent platform could depose Windows from its pedestal.

If there’s one thing we like more than a good tech joke then, it’s a well-written tech rant, and [Artem S. Tashkinov] has penned a doozy in “Why Linux is not ready for the desktop, the final edition“. It’s Linux trolling at its finest, and will surely get many a crusty open source devotee rushing to their keyboard to decry its ideas.

Aside from the inherent humor then, reading it we have to admit that he makes a set of very cogent points. Even having used a Linux desktop exclusively for a very long time indeed there’s no shame in admitting that it’s not perfect, and things such as the mildly annoying state of network file sharing or the complexity for most users of getting to grips with the security model are very fair criticisms. And the last section on the Linux community hits hard, it’s necessary to admit that the world of open source doesn’t always welcome people trying to use its software as well as it could.

But as power users of a Linux desktop for everything, more than just for writing Hackaday, we’d take the view that for all its undoubted faults, it still offers a better experience than the latest version of Windows. Oddly it could now be an acceptable desktop for many people, but the sad thing is that the need for that may well have passed to those Android and Chrome OS devices we mentioned earlier.

We’ve been known to have our own Linux related rants from time to time.

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.