See Aerodynamics In Action With A Desktop Wind Tunnel

May 27, 2026 by Jenny List 10 Comments

While most of us don’t design aircraft or racing cars, it’s likely that we’re still fascinated by some of the aerodynamic studies behind them. But a full-sized wind tunnel is going to cost a small fortune, so how can we experiment? Never fear, because [luisengineering] is here with a 3D printable desktop wind tunnel.

There’s a build video that we’ve embedded below, and if you can sit through the continuous shilling of random tools, it’s an interesting watch. It’s an open design in that air is not recirculate through it, instead it passed through the machine from left to right. On the right is the fan, on the left the intake with a rectifier to ensure laminar flow. Then a constriction compresses and speeds up the air past the stage for the model under test, and an expansion slows it down again for the fan.

A wind tunnel needs a smoke generator to easily spot turbulence, and in this case a vape is called into action. The result is surprisingly effective, as we see with a demonstration using a small model car. Meanwhile if you’re interested in wind tunnels at this size, it’s not the first one we’ve brought you.

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A ZInc Air Battery You Can Make Yourself

May 26, 2026 by Jenny List 9 Comments

Zinc air batteries have been a familiar sight for decades in the world of photography, where they provided an environmentally less dangerous alternative to mercury cells. They operate by the oxidation of metallic zinc using air, and the zinc comes in the form of a paste spread between two electrodes. Can their astounding energy density be harnessed for something useful? [ZollerLab] has designed a zinc air battery to find out, and is using it to power a rudimentary model car.

The video below is in German so you’ll have to enable translated subtitles if you’re an Anglophone, and it’s very long. But it goes into extreme detail on the chemistry, construction, and constraints of a zinc-air battery, and describes the system in this design. It’s a stack arrangement, in which the cells are held together on threaded rods, and pushed into each other with springs.

We think the car model is intended to demonstrate that this battery chemistry might one day be used in automotive applications. It’s not such a far-fetched idea given the low cost, relatively low environmental footprint, and high energy density, indeed we’ve heard of similar experiments with aluminium primary cells. But in this case we can see it provides the hacker with another route for their experiments, and that’s no bad thing.

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The Email Of The Future In 1986

May 24, 2026 by Jenny List 26 Comments

With so many online messaging services to choose from it’s almost as though the daddy of them all, email, has faded into the background as something you only use for more formal contacts. But it’s still the underpinning of much of the business world’s electronic communication and is likely to stay so for the foreseeable future. The BBC Archive takes us back to a time when email was relatively new, when in 1986 [Lesley Judd] takes a very chunky 1980s laptop on a plane from London to the Netherlands, and sends an email to her colleague at home using a payphone and an acoustic coupler.

There are so many of-their-era quirks in this film it’s difficult to pick, but little things like the aircraft still having smoking and non-smoking areas, there being no sign of a mobile telephone, or the payphone operating in Guilders rather than Euros make it from a different time. Perhaps most interesting though is the email system in use, because this isn’t an internet based service. Instead it’s using Telecom Gold, which was the UK telco BT’s online service offering to businesses, and part of the international Dialcom network. This was a commercial service which hung on until some time in the 1990s when the Internet finally displaced it.

The British writer L. P. Hartley used the phrase “The past is a foreign country; they do things differently there” as the opening sentence of one of his books, and the film below the break certainly brings that to mind. It’s a time that’s within reach, yet the changes in information technology over even the next decade or so would make the tech depicted not just obsolete but almost unrecognizable. Most of us today could sit at a 1996 laptop and send an email, but few of us would be as immediately at home with Telecom Gold.

It’s still possible to use an acoustic coupler today though.

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Bring Back That Aged Scanner, In Your Browser

May 20, 2026 by Jenny List 37 Comments

We have probably all at some point had to replace a peripheral not because it is faulty, but because it is no longer supported by our operating system. It’s especially bad for Windows users, but for older hardware this is increasingly a part of the Linux experience too. [George MacKerron] is here with what may prove to be a valuable technique to keep these devices active. He’s running a minimalist x86 computer in the browser, with just enough OS to support the device.

In this case the hardware is a USB scanner, and the resulting software takes a WebAssembly x86 emulator and adds a bit of glue software allowing it to use WebUSB to talk to the real-world hardware. It runs a minimal Alpine Linux environment with SANE — something that’s normal for Linux users but which has never been there on a Windows machine. The result is something which needs no installation, but can be run on any machine with a powerful enough web browser.

While such an approach might at first seem like overkill, we’re told it runs surprisingly quickly. In this case it’s for scanner, but we can see it could find a use with many other pieces of aged hardware.

If WebAssembly is new to you, we gave it a primer a few years ago.

Header image: Fir0002/Flagstaffotos, GFDL 1.2.

CGA As You Have Never Seen It Before

May 17, 2026 by Jenny List 11 Comments

An old-style graphics system as found on many 8-bit computers and on early PC graphics cards drew its characters by retrieving their bitmaps from a ROM. With a little sideways thinking, [GloriousCow] has exploited this process to make a CGA card perform graphical tricks it was never designed to do.

The CGA card clocks its character ROM continuously across the whole screen, even at the edges where nothing would normally be displayed. By placing the ROM in tandem with a Raspberry Pi Pico 2 they were able to use this ROM clocking as a synchronization signal, and inject whatever pixel data they chose.

The result is a CGA card that can display 60 Hz high-res graphics in text mode, albeit with a very retro one bit color depth. It can overlay the text and the graphics too, because the ROM is still present. One fun result of this is a bouncing DVD logo screensaver, on a DOS PC.

There’s a PCB and a promise of more, meanwhile we suggest you take a look at an impossible feat using a similar technique: NES Doom.

An E-Bike Motor From First Principles

May 14, 2026 by Jenny List 17 Comments

Many of us have made electric transport of some form, whether a Hacky Racer, and e-bike, a go-kart, or whatever. We have invariably bought a motor, or if we are really adventurous, repurposed a car alternator. Not [Birdbrain] though, because she’s designed and built her own from first principles.

The video below goes into significant detail on the design of her motor, looking at cores, wire sixes, and configurations with a useful simulation along the way. We particularly like the way she uses a bandsaw to cut transformer laminations to shape for her core. The 3D printed housing initially isn’t strong enough for the forces induced by the magnets, but she attacks that problem with a new print. The motor works well, and as an added bonus there’s an introduction to the different types of motor driver. It seems the cheap ones don’t deliver a good waveform for the characteristics of the motor. Sadly she doesn’t fit it to a real bike in the video, but it seems this thing might just work.

If you lack the courage to make the whole thing from scratch, we took a quick look at the car alternator route a while back.

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British Street Addresses, When Licenses Collide

May 14, 2026 by Jenny List 27 Comments

The world of open source — and in particular open source licenses — is something we cover regularly here at Hackaday with respect to hardware and software, but it’s not so often we find open source data stories. Today’s case of the open British address data then is a bit of an outlier, but it may have implications for open source data further than British counties.

UK government data is released under the Open Government Licence, which is why we Brits can peer into all sorts of datasets our taxes paid for. This includes data from local government, so English counties release data sets of local addresses as part of their auditing of council taxes under the licence.

This is a picture of Barbra Streisand, who might almost be the patron saint of unintended consequences. Unknown author / Public domain — This is a picture of Barbra Streisand, the patron saint of unintended consequences.

[Owen Boswarva] has been collating these databases in order to produce a national open source address database, but has found himself at the receiving end of a legal threat from the Ordnance Survey, the UK mapping agency. They claim the data is theirs, not open.

British address data is in a sense open to all, in that there’s nothing to stop anyone walking down Acacia Avenue and noting the position of Number 1, Number 2, Number 3, and so on. This is what happened with OpenStreetMap worldwide, as people with GPS devices contributed their data and mapped the UK and everywhere else. The Ordnance Survey used to have a nice little earner charging top dollar for UK geospatial data which has been slashed by the arrival of OpenStreetMap, and we’re guessing that the prospect of losing another income stream to an open source equivalent has them worried.

The question of whether the councils should have released the data is one which will no doubt be settled at some point by the courts, and [Owen] goes into some detail on the subject in his analysis. There’s a good case to be made that the mapping agency are pushing it a little, but whatever the outcome it could set a dangerous precedent for open source data. We’ll keep you posted if there’s more on this story.

British street: Bill Harrison, CC BY-SA 2.0

Barbra Streisand: Unknown author, Public domain