Developing A 4,500 RPM Twin-Cylinder Air Engine

September 4, 2023 by 19 Comments

Compressed air isn’t really a practical form of energy storage for headline uses like transport or heating, but it’s a fun thing to tinker with at the small scale. [Tom Stanton] is plenty experienced in that area, having built a series of compressed air engines over the years. His latest effort is capable of running at up to 4,500 RPM, and delivering a full 0.05 horsepower.

Two-cylinder power!

[Tom’s] ultimate goal is to put his new tiny air engine on a small model aircraft. To enable consistent performance, his engine needs a regulator, but off-the-shelf models for industrial use were too hefty for his use. Thus, he set about equipping his engine with a lightweight regulator of his own 3D-printed design.

His latest ball-valve air engine was then designed to run on this lower regulated pressure of approximately 30 psi. It initially proved less efficient than his previous designs, but some engineering analysis revealed the problem. [Tom] does a great job of stepping through his process of understanding how these engines perform, and how he uses these findings to guide his design choices going forward.

It’s also great to see a YouTuber not just building fun things, but taking measurements and doing some real engineering. [Tom’s] air engines keep getting better, and we can’t wait to see where he takes his designs next.

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The McDonald’s Ice Cream Machine Saga And Calls For Right To Repair

August 30, 2023 by 45 Comments
The inside of a Taylor C709 ice cream machine, as seen from the back with the cover on the electronics removed. (Credit: iFixit)
The inside of a Taylor C709 ice cream machine, as seen from the back with the cover over the electronics removed. (Credit: iFixit)

Raising a likely somewhat contentious topic, iFixit and Public Knowledge have challenged the manufacturer behind McDonald’s ice cream machines to make them easy to diagnose and repair. This is a subject that’s probably familiar to anyone who is vaguely familiar with US news and the importance of ice cream at McDonald’s locations to the point that a live tracker was set up so that furtive customers can catch a glimpse at said tracker before finding themselves staring in dismay at an ‘Out of Order’ sign on one of these Taylor ice cream machines.

The story is more complex than just a machine being “broken”, however. The maintenance contracts are lucrative, the instruction manual is long, and the error codes are cryptic. When you add to that the complexity of cleaning and maintaining the machines, it’s tempting to just claim the machine is out of order. These Taylor machines (the C602 and the C709 from the iFixit video) are a bit more complex than your usual ice cream maker in that they also have a pasteurization element that’s supposed to keep already poured mix safe to use the next day.

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Maker Faire Hannover: The Right Way To Do It

August 28, 2023 by 16 Comments

On these pages we bring you plenty of reports from events, most of which are from the hacker or hardware communities. These can be great fun to attend, but they’re not the only game in town when looking at things adjacent to our community. At what you might describe as the consumer end of the market there are the Maker Faires, which bring a much more commercial approach to a tech event. While so many of us are in Germany for Chaos Communication Camp there’s a maker faire ideally placed to drop in on the way back. We took the trip to Hannover, a large and rather pleasant city just off the Berlin to Amsterdam motorway roughly central to the top half of the country. It’s got one of the German emissions zones so without the green tax sticker in the car we took a park-and-ride on one of their clean and efficient trams to alight a short walk from the congress centre.

Plenty To See, And It’s Not All For Kids

An array of European electronic conference badges on show
Outside, a working forge
Face it, we all want a clock like this one!
Vintage test equipment
You may know Bitluni from many featured projects here.
A group of Germans who maintain a 1990s TV studio.
Hackaday’s first post, courtesy of the Wayback Machine and Makerspace Minden.

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Sharkskin Coating Reduces Airliner Fuel Use, Emissions

August 23, 2023 by 66 Comments

The aviation industry is always seeking advancements to improve efficiency and reduce carbon emissions. The former is due to the never-ending quest for profit, while the latter helps airlines maintain their social license to operate. Less cynically, more efficient technologies are better for the environment, too.

One of the latest innovations in this space is a new sharkskin-like film applied to airliners to help cut drag. Inspired by nature itself, it’s a surface treatment technology that mimics the unique characteristics of sharkskin to enhance aircraft efficiency. Even better, it’s already in commercial service! Continue reading “Sharkskin Coating Reduces Airliner Fuel Use, Emissions” →

Off-Grid Radio Also Repairable Off-Grid

August 19, 2023 by 33 Comments

Low-power radios, often referred to in the amateur radio community as QRP radios, have experienced a resurgence in popularity lately. Blame it on certain parts of the hobby become more popular, like Parks on the Air (POTA) or Summits on the Air (SOTA). These are events where a radio operator operates off-grid at remote parks or mountaintops. These QRP rigs are a practical and portable way to make contacts. You would think that a five- or ten-watt rig running on batteries would be simple. Surprisingly, they can be enormously complex and expensive. That’s why [Dr. Daniel Marks] built the RFBitBanger, a QRP radio designed to not only be usable off-grid but to be built and maintained off-grid as well.

The radio accomplishes this goal by being built out of as many standard off-the-shelf components as possible. It eschews modern surface-mount components in favor of the much more accessible through-hole parts, including the ATMEGA328P at the center of the build. A PCB design is also available, but it can be built on perf board nearly as easily. The radio supports any mode a QRP operator might use, including CW, SSB, RTTY, and a new mode designed explicitly for this radio called SCAMP which is a low bandwidth, low SNR digital mode built into the Arduino-based firmware. It’s a single-band radio, but any band between 20 and 80 meters can be selected with pluggable filters.

As far as bomb-proof radios go, we can’t imagine a better way to live out an apocalypse than with a radio like this. As long as there’s a well-stocked parts drawer around, this radio could theoretically reach around the world without worrying about warranty claims, expensive parts, or even a company going out of business or not stocking parts for old radios anymore. There’s also more information about this build at the Open Research Institute for those interested. And, if you’re wondering how useful any radio could be using only five watts of transmitter power, take a look at this in-depth look at QRP radio operation.

Thanks to [Stephen Walters] for the tip.

Repairing A Home Injection Molding Machine

August 5, 2023 by 10 Comments

When [Michael] over at the Teaching Tech YouTube channel bought a hobby injection molding machine a long time ago, one of the plans he had with it was to use it for grinding up waste bits of PLA filament for injection molding. Since the machine was bought from a US shop and [Michael] is based in Australia it required some modifications to adapt it to the local 220+ VAC mains, followed by adding a PID temperature controller and a small compressor to provide the compressed air rather than from a large shop compressor.

Although [Michael] had discussed using the machine for PLA with the seller to confirm that this would work, a user error meant that the now defective unit had been sitting idly for many years, until recently.

Since the machine had been gathering dust and rust in the garage, fixing the machine up took a complete teardown to remove corrosion and resolve other issues. After this the original fault was identified, which turned out to be a shorted wire near the heater which had been turned up to a too high temperature, leading to the release of magic smoke and banishment of the machine to the Pit of Despair, AKA the shadowy depths of one’s garage.

In this first installment, [Michael] cleaned up the machine and restored it to a working state. In the next part injection molding will be attempted again, which should give some idea of the feasibility of turning scraps of PLA and failed 3D prints into smooth injection molded parts, assuming you have the CNC machine or patience to carve out the requisite molds, of course.

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3D Print Your Best Friend A Wheelchair

August 4, 2023 by 7 Comments

We all know that 3D printing has been a boon for people with different life challenges. But the Ford Motor Company in Mexico wants to help dogs that need mobility assistance. They’ve designed and released P-Raptor (we presume the P is for perro), a wheelchair for pooches with rear leg issues. The web page is in Spanish, and translating it didn’t seem to work for some reason, but if you have any Spanish, you can probably work it out or cut and paste just the text into your favorite translator.

The design is modular to adapt to different size dogs and different problems. It contains an electric motor in the tires. The tires themselves are oversized to help your friend cover rugged terrain. Dogs want to look cool, too, so a grill with lighting is included.

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