Electromagnetic Mechanism Makes Reconfigurable Antenna

February 22, 2023 by Al Williams 10 Comments

Antennas are a key component to any RF gadget. But antennas often only perform well over a narrow band of frequencies. For some applications, this is acceptable, but often you would like to reconfigure an antenna for different bands. Researchers at Penn State say they’ve developed a tunable antenna using compliant mechanisms and electromagnets. The new scalable design could work in small areas to provide frequency agility or beamforming.

The prototype is a circular patch antenna made with 3D printing. If you want to read the actual paper, you can find it on Nature Communications.

A compliant mechanism is one that achieves force and motion through elastic body deformation. Think of a binder clip. There’s no hinge or bearing. Yet the part moves in a useful way, using its own deformation to open up or grip papers tightly. That’s an example of a compliant mechanism. This isn’t a new idea — the bow and arrow are another example. However, because 3D printing offers many opportunities to build and refine devices like this, interest in them have increased in recent years.

We couldn’t help but notice that the antenna is a variation of a “compliant iris” like the one in the video below. You can find designs for these online for 3D printing, so if you wanted to experiment, you might think about starting there.

We’ve looked at compliant mechanisms before. Why would you want better chip-scale antennas? Why, indeed.

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Let Machine Learning Code An Infinite Variety Of Pong Games

February 21, 2023 by Dan Maloney 7 Comments

In a very real way, Pong started the video game revolution. You wouldn’t have thought so at the time, with its simple gameplay, rudimentary controls, some very low-end sounds, and a cannibalized TV for a display, but the legendarily stuffed coinboxes tell the tale. Fast forward 50 years or so, and Pong has been largely reduced to a programmer’s exercise to see how few lines of code can stand in for what [Ted Dabney] and [Allan Alcorn] accomplished. But now even that’s too much, as OpenAI Codex can generate a playable Pong from just a few prompts, at least most of the time. Continue reading “Let Machine Learning Code An Infinite Variety Of Pong Games” →

Tiny11 Makes Windows 11 Small

February 21, 2023 by Al Williams 81 Comments

If you often spin up a virtual machine just to run Windows, you might be sad that you have to allocate so much space for it. The Tiny11 project provides a Windows 11 installer that strips and compresses a bare minimum system do under 8GB of space. We aren’t sure what the licensing aspects of it all mean, but there are a few things you need to know. You can see a video about the project below.

The installer requires you to activate Windows, so that’s probably a good thing from a legal standpoint. Besides being compressed, the installer, based on Window 11 Pro 22H2, removes sponsored applications and Teams. It does, however, have the component installer and the Microsoft store, so you can add back things you want that aren’t in the default install.

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OpenStructures Is A Modular Building System For The RepRap Age

February 21, 2023 by Navarre Bartz 24 Comments

Modular construction toys like LEGO and Meccano are great for prototyping, but they aren’t so great for large builds. OpenStructures promises to be a modular building system for projects large and small.

Originally conceived in 2007 by [Thomas Lommée], OpenStructures is a modern, more robust reinterpretation of Grid Beam, which was itself a reinterpretation of the earlier Living Structures. By using a common standard (PDF), parts can be reused project after project as they would with LEGO, meaning you can spend more time building and less time cutting or figuring out joints. OpenStructures parts need connection points, part diameters, or part dimensions at multiples of 20 mm to be compatible. To fulfill the spirit of the project, parts should be designed for disassembly, use recyclable materials when possible, and be Open Source.

The system seems like a great starting point for prototyping furniture or other large builds more quickly than building everything on a case-by-case basis. By including diameters for round objects as well as square and rectangular profiles, OpenStructures is a more flexible (and aesthetically pleasing?) option than Grid Beam.

A couple more options for furniture-scale modular construction are these big LEGO bricks or copper pipe.

(via Low Tech Magazine)

Travel The World Looking For Retro Tech, Virtually

February 21, 2023 by Tom Nardi 1 Comment

For those who have a passion for vintage hardware, whether it be a classic computer or a war-surplus ham radio rig, finding the things without resorting to paying shipping fees on eBay can sometimes be tricky. Your best bet is to find a local fair or swap event, but it always seems they’re the kind of thing you find out about the weekend after they were held.

Looking to make these sort of events more visible and easier to keep track of, [RobSmithDev] has created the Retro.Directory. Scrolling your way across the globe you can see markers that indicate places of interest for the retro aficionado, such as museums, repair shops, and old school arcades, as well as upcoming events. Continue reading “Travel The World Looking For Retro Tech, Virtually” →

Retro Gadgets: Make Your Scope Dual Channel

February 21, 2023 by Al Williams 32 Comments

We live in a time when having an oscilloscope is only a minor luxury. But for many decades, a good scope was a major expense, and almost no hobbyist had a brand new one unless it was of very poor quality. Scopes were big and heavy and, at the price most people were willing to pay, only had a single channel. Granted, having one channel is better than having nothing. But if the relative benefit of having a single channel scope is 10 points, the benefit of having two channels is easily at least 100 points. So what was a poor hacker to do when a dual-trace or higher scope cost too much? Why, hack, of course. There were many designs that would convert a single trace scope into a poor-quality multichannel scope. Heathkit made several of these over the years like the ID-22, the ID-101, and the ID-4101. They called them “electronic switches.” The S-2 and S-3 were even earlier models, but the idea wasn’t unique to Heathkit and had been around for some time.

For $25, you could change your scope to dual trace!

There were two common approaches. With alternative or alt mode, you could trigger a sync pulse and draw one trace. Then trigger again and draw the second trace with a fixed voltage offset. If you do this fast enough, it looks like there are two traces on the screen at one time. The other way is to rapidly switch between voltages during the sweep and use the scope’s Z input to blank the trace when it is between signals. This requires a Z input, of course, and a fast switching clock. This is sometimes called “chopper mode” or, simply, chop. This wasn’t just the realm of adapters, though. Even “real” analog scopes that did dual channels used the same methods, although generally with the benefit of being integrated with the scope’s electronics.

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