Magnus-Effect RC Aircraft Is A Lot Harder Than It Looks

August 5, 2021 by 13 Comments

Conventional airfoil wings have come out on top for getting flying machines airborne over the last century, but there were a few other interesting designs that have come and gone. One of these is the Magnus effect plane, which makes use of the lift produced by a spinning cylinder. [James Whomsley] from [Project Air] decided to build one as a side project, but it ended up being a lot more challenging than what he initially suspected. (Video, embedded below.)

The Magnus effect achieved a bit of viral fame a few years when [How Ridiculous] dropped a basketball down a dam wall with some backspin. [James] T-shaped Magnus effect plane has a pair of spinning cylinders at the top to create lift, driven by a brushless motor using a belt. A second brushless motor with a propeller is on the center carbon fiber tube provides forward thrust, and a rudder provides yaw control. The battery is attached to the bottom of the tub for stability.

The very first flight looked very promising, but [James] quickly ran into a series of problems related to center of gravity, power, pitch control, and drag. After iterations of the build-crash-rebuild cycle, he ended up with larger motors and rudder, shorter “wings”, and a higher thrust motor position. This resulted in a craft still only marginally controllable, but stayed in the air for quite a while. Since the intention was never to turn it into a long-term project, James] called it a success to avoid more yak shaving, and continue work on his airboat and rocketplane.

If you are interested in building one of your own, he put all the findings of his experimentation in a short report. For more inspiration, check out the other Magnus effect plane we covered that used KFC buckets for the wings.

Continue reading “Magnus-Effect RC Aircraft Is A Lot Harder Than It Looks” →

Hands On: DEF CON 29 Badge Embraces The New Normal

August 5, 2021 by 13 Comments

To say that 2020 was a transformative year would be something of an understatement. The COVID-19 pandemic completely changed the way we worked, learned, and lived. Despite all those jokes about how much time people spend on their devices rather than interacting face-to-face with other humans, it turns out that when you can’t get more than a few people together in the same room, it throws our entire society into disarray.

Our community had to rethink how we congregated, and major events like HOPE, DEF CON, and even our own Hackaday Supercon, had to be quickly converted into virtual events that tried with varying degrees of success to capture the experience of hundreds or thousands of hackers meeting up in real life. While few would argue that a virtual hacker convention can ever truly replace a physical one, we learned there are undeniable benefits to embracing the advantages offered by cyberspace. If nothing else, the virtual hacker meetups of 2020 saw a far larger and more diverse array of attendees and presenters than ever before.

As we begin seeing the first rays of light at the end of the long, dark, tunnel we’ve been stuck in, it’s clear that some of the changes that COVID-19 forced on our community are here to stay. As eager as we all are to get back to the epic hackfests of old, nobody wants to close the door on all those who would be unable to attend physically now that they’ve gotten to peek behind the curtain.

With this in mind, this year’s DEF CON is being presented in both physical and virtual forms simultaneously. If you made to Las Vegas, great. If not, you can follow along through chat rooms and video streams from the comfort of your own home. Following the theme, the DC29 badge is not only a practical tool for virtual attendees, but an electronic puzzle for those who are able to bring a few of them together physically. Let’s take a closer look at this socially distanced badge and the tech that went into it.

Continue reading “Hands On: DEF CON 29 Badge Embraces The New Normal” →

Vintage Computer Festival West Is This Weekend

August 5, 2021 by 4 Comments

This weekend is the Vintage Computer Festival (VCF) West, which will be held in-person at the Computer History Museum in Mountain View, California. Here is the complete schedule of events.

If you’re in the area, go get your retrocomputing on at this two-day event that Hackaday are proud to sponsor. Who knows? You may end up hobnobbing with original system developers who are finally at liberty to spill the tea about the old days.

Case in point: Hackaday’s own Bil Herd will be there virtually to talk about the new Commodore inside history book he wrote with Margaret Moribito. Other speakers include Bob Purvy, who will discuss his novel about the Xerox Star. This isn’t your average history book — it uses fictional characters to play out actual events. Another talk delves into the history of computerized tic-tac-toe, and yet another will cover recovering lost floppy disks with an oscilloscope. Finally, Liza Loop will speak about the history of computing in education to close out the weekend’s talks.

There are also plenty of exhibitions on the schedule, too, including Rare Computers from Japan and Analog Computing in the 1960s. And don’t forget, you’re at the Computer History Museum, so there should never be anything approaching a dull moment. Have fun!

Linux Fu: The Windows X11 Connection

August 5, 2021 by 38 Comments

The life of a Linux user can be a bit difficult. Sometimes you have to — or want to — run Windows. Why Windows? Sometimes you have a work computer or a laptop that Linux doesn’t support well. Or it might be software. Although there are plenty of programs that can edit, say, Word documents, there’s always that one document that doesn’t quite translate correctly. Things like videoconferencing software sometimes works on Linux but might have fewer features.

So what do you do? You can dual boot, of course, but that’s not very handy. You can run Windows in a virtual machine if you have enough horsepower. There’s also Wine, but that often has its own set of problems with features and stability of complex programs. However, recent versions of Windows provide the Windows Subsystem for Linux (WSL).

With WSL, you can have most of what you like about Linux inside your Windows session. You just have to know how to set it up, and I’m going to show you one way that works for me with reasonably stable versions of Windows 10. Continue reading “Linux Fu: The Windows X11 Connection” →

This Is A 3D Ink Jet Printer

August 5, 2021 by 15 Comments

We spend a lot of time thinking of how to create 3D objects, but what about being able to print full color graphics on the objects we create? This isn’t just multicolor, this is full-color! Here’s one elegant solution that uses ink jets to print full color images on 3D terrain models.

Admittedly we are very late to the party on this one as the technology was spotted on season 22, episode 7 of How It’s Made that aired way back in 2013. The segment shows terrain models — think of the physical contour map under glass that you might see at a National Park or at the main lodge of a ski resort. It’s easy enough to envision how the elevation is carved out of foam by a CNC. But the application of color printing to those surfaces is what caught our eye this time around. It’s a custom rig that a company called Solid Terrain Modeling built for this purpose. Since the height at any point on the work material is already known from the milling process, four ink heads (black, cyan, magenta, yellow) have been added to individual Z-axis actuators, applying a raster image as they traverse the surface.

Part of what makes this work is the post-processing steps that follow milling. The model is very carefully cleared of debris before being sprayed with primer. Another coat of an undetermined material (“a specialty coating to receive the ink”) gets the piece ready for the ink. The final step after printing is a protective clear coat. In the How It’s Made episode, buildings and other structures are then 3D-printed and added.

It seems like the trick is to get the heads to have as small of a footprint as possible for clearance when printing in sloped areas. We’re not experts in all the available consumer ink-jet printers out there, but finding a setup where the heads are separated from the reservoirs would be key. Watching this segment made us so excited to think of the person/people who got to hack this rig together as part of their job.

Looking for other ways to abuse ink jet parts? [Sprite_TM] came up with a way to make them handheld so you print on anything from latte foam to your buddy’s forearm. There’s no better name for that than the Magic Paintbrush.

Continue reading “This Is A 3D Ink Jet Printer” →

Knowing The Bits And Bytes That Make Images Live In Memory

August 5, 2021 by 16 Comments

We know we’re living in the future because there’s hi-resolution, full color images plastered on every high-density screen in sight. Of course this comes at a cost, one that’s been hidden away by the myriad improvements in the way we digitally represent those pretty pixels and how we push them to the screens. Nobody thinks about this, except those who are working behind the screen to store and light up those pixels. And hey, chances are that’ll be you some day. Time to learn a bit more about image encoding!

Test renders illustrate the time savings from premultiplied alpha formats

[Scott W Harden] put together a succinct primer on representing images in memory. It focuses on the basics of how images are stored: generally with the B before the G, sometimes including an alpha (transparent) channel, and with a number of different bit depths. Having these at the front of your mind is crucial for microcontroller projects, where deciding what types of images to support is often limited by the amount of memory available for frame buffers, and the capabilities of the screen chosen as the device’s display.

Speaking of display specifics, [Scott] shares some detail about mapping the memory to the dimensions of your screen. If the byte count of pixel data doesn’t line up nicely with the dimensions of the screen, padding the rows out may help in the processing overhead it takes to get those pixels onto the screen. He also has some tips about “premultiplied alpha” which makes the transparency calculation a part of the image itself, rather than demanding this be done when trying to update the screen. Running a test in C# on one million frame renders shows the type of savings you can expect.

Decades of trial and error landed us with these schemes. Looking back is literally an archaeology project, as one hacker discovered when trying to get a set of digital images off of a floppy from a 1990s photo processing service.

Light Bulb Plant Propagation Station Is A Bright Idea

August 4, 2021 by 11 Comments

We’ve always enjoyed having a few indoor plants around the Hackaday dungeon because they just make the days more cheerful. Apparently there’s a big craze for them right now, which has led to price increases of things like propagation stations — places where cuttings from mature plants go to grow a root system before getting planted in dirt. Many plants will root readily in water, and it’s better for them to start out this way because soil can come with a bunch of problems.

This goes really well with the older craze of Edison-style light bulbs. We’re glad we never bothered with those because [JGJMatt] says they don’t last long at all. The bulbs themselves are really nice looking, so [JGJMatt] decided to turn a few of them into hanging water propagation stations. After cleaning out the bulb and embiggening the opening, [JGJMatt] formed a holder by applying a torch to brass rod. This dulls the brass, so they shined it up with steel wool and some automotive polishing compound. Then it’s time for some simple macrame to hang it with, because it will soon be full of water.

Does the handle sound familiar? It ought to — [JGJMatt]’s elegant builds have graced these pages a few times before.