Day: February 21, 2024

Replacement PCB Replicates Early 80s Modem

February 21, 2024 by 27 Comments

It’s certainly been a few decades, but plenty of us remember a time before widespread access to broadband internet, when connections were generally made over phone lines using acoustic modems. In the 90s these could connect you to AOL and Napster well enough, but in the early 80s the speeds were barely enough to read text as it loaded. A company called Hayes set out to change this with some of the first useful, widely-available modems for the PCs at the time. While they couldn’t keep up with the changing times there’s still a retro community that has these antiques, and to modernize it a bit this drop-in replacement for the PCBs replicates these old modems almost exactly.

The new PCB is equipped with everything needed to get a retro computer online again, including all the ports to connect a computer without any further modifications. It houses a few modern upgrades beyond its on-board processors, though. Rather than needing an actual acoustic coupled phone, this one has an ESP32 which gives it wireless capability. But the replacement PCB maintains the look and feel of the original hardware by replicating the red status LEDs at the front, fitting into the original Hayes cases with no modifications needed at all, and even includes a small speaker through which it can replicate the various tones, handshakes, and other audio cues that those of us nostalgic for this new online era remember quite well.

For those looking for a retro feel without the hassle of getting antique networking equipment functional again, this type of upgrade that preserves the essence of the original hardware is an excellent way of keeping retro computers functional on modern networking equipment. But if you absolutely must get the networking equipment exactly right down to the last patch cable, you might end up having to build your own ISP from scratch.

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A large array of triangles and colored lines showing the folding pattern of the origami computer

Turing Complete Origami

February 21, 2024 by 6 Comments

Origami can be an interesting starting point for a project, but we weren’t expecting [Thomas C. Hull] and [Inna Zakharevich]’s Turing complete origami computer.

Starting with the constraint of flat origami (the paper folds back on top of itself), the researchers designed a system that could replicate all the functionality of the previously-proven Turing complete Rule 110 automaton. The researchers walk us through the construction of AND, OR, NAND, NOR, and NOT gates via paper as well as the various “wires” and “gadgets” that connect the operators or filter out noise.

Everything ends up a large mess of triangles and hexagons with optional creases to make the whole thing work. While the origami computer probably won’t be helping you slice 3D prints anytime soon, much like a Magic computer, the engineering and math involved may prove useful in other applications.

We’re no strangers to origami here, having covered origami machines, medical robots, or using a desktop vinyl cutter to pre-score your project.

FLOSS Weekly Episode 771: Kalpa — Because Nobody Knows What Hysteresis Is

February 21, 2024 by 6 Comments

This week, Jonathan Bennett and Dan Lynch talk with Shawn W Dunn about openSUSE Kalpa, the atomic version of openSUSE Tumbleweed, with a KDE twist. What exactly do we mean by an Atomic desktop? Is ALP going to replace openSUSE Tumbleweed? Are snaps coming to Kalpa?

Shawn gives us the rundown of all the above, and what’s holding back a stable release of Kalpa, what’s up with Project Greybeard, and why Kalpa really doesn’t need a firewall.

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Rebuilding A $700k Refrigerator

February 21, 2024 by 20 Comments

When cleaning out basements, garages, or storage units we often come across things long forgotten. Old clothes, toys, maybe a piece of exercise equipment, or even an old piece of furniture. [Ben] and [Hugh] were in a similar situation cleaning out an unused lab at the University of California Santa Barbara and happened upon an old refrigerator. This wasn’t just a mini fridge left over from a college dorm, though. This is a dilution refrigerator which is capable of cooling things down to near absolute zero, and these scientists are trying to get it to its former working state.

The pair are hoping to restore the equipment to perform dark matter experiments, but the refrigerator hasn’t been in use since about 2016 (and doesn’t have an instruction manual), which is a long time for a piece of specialty scientific equipment to be collecting dust. The first step is to remove wiring and clean it of all the grime it’s accumulated in the last decade. After that, the pair work to reassemble the layers of insulation around the main cooling plate and then hook up a vacuum pump to the device which also needed some repair work.

The critical step at this point is to evacuate the refrigerant lines so they can be filled with expensive Helium-3 and Helium-4. The problem is that there’s still some of this valuable gas in the lines that needs to be recovered, but the risk is that if any air gets into the cold section of the refrigerator it will freeze and clog the whole system. After chasing some other electrical and vacuum gremlins and discovering a manual from a similar refrigerator, they eventually get it up and running and ready for new scientific experiments. While most of us won’t discover a fridge like this cleaning out our attics, this refrigerator powered by rubber bands is a little more accessible to the rest of us.

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Spectrum Analyzer Buyer’s Guide

February 21, 2024 by 8 Comments

Having a scope in a home lab used to be a real luxury, but these days, its fairly common for the home gamer to have a sophisticated storage scope (or two) hanging around. Dedicated spectrum analyzers are a bit less common, but they have also dropped in price while growing in capabilities. Want to buy your very own spectrum analyzer? [Kiss Analog] has a buyer’s guide for what to consider.

If you’ve already got a scope, it may have a Fast Fourier Transform (FFT) function, and he talks about how it could be used in place of a spectrum analyzer or vice versa. But it really depends on what you’re planning on using it for. If you’re doing compliance testing for emissions, an analyzer is invaluable. If you like building transmitters or even just oscillators for other purposes, viewing the output on a spectrum analyzer can show you how well or poorly your design is performing. Any application where you need to visualize large swaths of the RF spectrum is a candidate for a spectrum analyzer.

Towards the end of the video, you’ll get to see some actual uses on a Uni-T UTS3021B. While those are at the higher end of the hobby price spectrum (no pun intended), it has many features that would have required an instrument ten times that price in years gone by.

There are also some very inexpensive options out there. While it is true, to a degree, that you get what you pay for, it is also true that even these cheap options would be amazing to an engineer from the 1990s. Yes, of course. You could do it with a 555.

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Power Tool Packs Make A Portable Powerhouse

February 21, 2024 by 15 Comments

The revolution in portable and cordless appliances has meant that we now own far fewer mains-powered gadgets than we might once have done, but it hasn’t entirely banished the old AC outlet from our lives. Particularly when away from a mains supply it can be especially annoying, but now instead of a generator there’s the option of an inverter. [Thijs Koppen] has made a very neat all-in-one mains power station in a plastic flight case using the ubiquitous and handy standardized Makita power tool packs.

From one perspective this is a simple enough build, because wiring a battery to an inverter isn’t the most difficult of tasks. But he’s designed his own 3D printed Makita battery receptacles which should be of interest to plenty of readers, and with three packs in series he’s sourced an unusual 72 volt inverter to supply mains. The photo of him charging a Tesla with the result is probably more for show than practicality though.

We’ve featured quite a lot of cordless tool battery hacks over the years as their ready availability and quick interchangeability is attractive. If you ever fancy engineering your own mounting, we’ve taken a look at someone doing just that.

Car Driving Simulators For Students, Or: When Simulators Make Sense

February 21, 2024 by 69 Comments

There are many benefits to learning to fly an airplane, drive a racing car, or operate some complex piece of machinery. Ideally, you’d do so in a perfectly safe environment, even when the instructor decides to flip on a number of disaster options and you find your method of transportation careening towards the ground, or the refinery column you’re monitoring indicating that it’s mere seconds away from going critical and wiping out itself and half the refinery with it.

Still, we send inexperienced drivers in cars onto the roads each day as they either work towards getting their driving license, or have passed their driving exam and are working towards gaining experience. It is this inexperience with dangerous situations and tendency to underestimate them which is among the primary factors why new teenage drivers are much more likely to end up in crashes, with the 16-19 age group having a fatal crash nearly three times as high as drivers aged 20 and up.

After an initial surge in car driving simulators being used for students during the 1950s and 1960s, it now appears that we might see them return in a modern format.

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