Upgraded Plasma Thruster Is Smaller, More Powerful

When [Jay Bowles] demoed his first-generation ion thruster on Plasma Channel, the resulting video picked up millions of views and got hobbyists and professionals alike talking. While ionic lifters are nothing new, this robust multi-stage thruster looked (and sounded) more like a miniature jet engine than anything that had come before it. Optimizations would need to be made if there was even a chance to put the high-voltage powerplant to use, but [Jay] was clearly onto something.

Fast forward six months, and he’s back with his Mark II thruster. It operates under the same core principles as the earlier build, but swaps out the open-frame design and acrylic construction for a rigid 3D printed structure designed to more effectively channel incoming air. The end result is a thruster that’s smaller and has a lower mass, while at the same time boasting nearly double the exhaust velocity of its predecessor. Continue reading “Upgraded Plasma Thruster Is Smaller, More Powerful”

Clever Mechanism Powers This All-Mechanical Filament Respooler

No matter how far down the 3D printing rabbit hole we descend, chances are pretty good that most of us won’t ever need to move filament from one spool to another. But even so, you’ve got to respect this purely mechanical filament respooler design, and you may want to build one for yourself just because.

We were tipped off to [Miklos Kiszely]’s respooler via the very enthusiastic video below from [Bryan Vines] at the BV3D YouTube channel. He explains the need for transferring filament to another spool as stemming from the switch by some filament manufacturers to cardboard spools for environmental reasons. Sadly, these spools tend to shed fibrous debris that can clog mechanisms; transferring filament to a plastic spool can help mitigate that problem.

The engineering that [Miklos] put into his respooler design is pretty amazing. Bearings excepted, the whole thing is 3D printed. A transmission made of herringbone gears powers both the take-up spool and the filament guide, which moves the incoming filament across the width of the spool for even layers. The mechanism to do this is fascinating, consisting of a sector gear with racks on either side. The racks are alternately engaged by the sector gear, moving a PTFE filament guide tube back and forth to create even layers on the takeup spool. Genius!

Hats off to [Miklos] on this clever design, and for the extremely detailed instructions for printing and building one of your own. Even if you don’t have the cardboard problem, maybe this would help if you buy filament on really big spools and need to rewind for printing. Continue reading “Clever Mechanism Powers This All-Mechanical Filament Respooler”

Customizing The Start-Up Chime On A 1999 G3 IMac

The start-up chime on Macs is probably as recognizable as the default Nokia ringtone in this day and age. Yet much like a ringtone, so too one might want to change the start-up chime on a Mac. This is something which [Doug Brown] has done in the past already on a Power Mac G3 in 2012, which made him instantly an expert on the topic in the eyes of a reader who wanted to know how to change the chime on a 1999 iMac. While the firmware on both these systems is written in Forth, it did take a bit of sleuthing to figure out where the chime was hiding in the firmware image, and how to change it.

The target iMac is somewhat unique in that it has a G4 PPC CPU rather than the more common G3. The firmware is similar enough that it was a snap to simply search the newer iMac’s firmware for the signature of the chime sound data. This turned out to be the identical QuickTime IMA ADPCM format-encoded data, yet what was different was how this data was integrated into the firmware image. Key is finding the area in the firmware where not only the address of the chime data’s start is defined, but also its length. Finally, the checksums in the firmware image have to be updated so that it matches the patched data.

Reverse-engineering the checksum calculation in the Forth code turned out to be fairly straightforward, but getting the new firmware on the iMac turned out to be the biggest struggle, as [Doug] didn’t want to inflict running a manual firmware update onto this reader he was doing all this work for. This led [Doug] to do some more reverse-engineering using Ghidra to enable the use of the automatic updater like a regular firmware update.

In the end it all worked out great, and now another iMac no longer has the Mac chime on start-up.

A Hacker’s Introduction To DIY Light Guide Plates

Last year, I found myself compelled to make a scaled-down replica of the iconic test chamber signs from the video game Portal. If you’ve played the game, you’ll remember these signs as the illuminated monoliths that postmarked the start of every test chamber. In hyperstylized video game fashion, they were also extremely thin.

Stay tuned for cake at the end of this article.

True to the original, my replica would need to be both slimmed down and backlit with a uniform, natural white glow. As fate would have it, the crux of this project was finding a way to do just that: to diffuse light coming in from the edges so that it would emit evenly from the front.

What I thought would be quick project ended up being a dive down the rabbit hole that yielded some satisfying results. Today, I’d like to share my findings and introduce you to light guide plates, one of the key building blocks inside of much of today’s backlit screen technology. I’ll dig into the some of the working principles, introduce you to my homebrew approach, and leave you with some inspirational source code to go forth and build your own. Continue reading “A Hacker’s Introduction To DIY Light Guide Plates”

A Thoroughly Modern Serial Terminal

The humble desktop serial terminal may have long disappeared from the world of corporate IT, but there are still plenty of moments when professionals and enthusiasts alike need to hook up to a serial port. Many of us use a serial port on our laptops or other mobile devices, but [Neil Crawforth] has gone one better than that with the VT2040. It’s an old-style serial terminal in a super-handy portable format, and as one might guess from the name, it has an RP2040 microcontroller at its heart.

Attached to the chip is a rather nice keyboard, and an ILI9488 480×320 LCD display. The software is modular, providing a handy set of re-usable libraries for the different functions including a PIO-based serial port. His main application seems to be talking to an ESP8266, but we’re guessing with a MAX232 or other level shifter chip it could drive a more traditional port. Everything can be found in the project’s GitHub repository, allowing anyone to join the fun.

As long-time readers will know, we’ve been partial to a few serial terminals in the past. Particularly beloved is this extremely retro model with vintage dot matrix LEDs.

Simultaneous Invention, All The Time?

As Tom quipped on the podcast this week, if you have an idea for a program you’d like to write, all you have to do is look around on GitHub and you’ll find it already coded up for you. (Or StackOverflow, or…) And that’s probably pretty close to true, at least for really trivial bits of code. But it hasn’t always been thus.

I was in college in the mid 90s, and we had a lab of networked workstations that the physics majors could use. That’s where I learned Unix, and where I had the idea for the simplest program ever. It took the background screen color, in the days before wallpapers, and slowly random-walked it around in RGB space. This was set to be slow enough that anyone watching it intently wouldn’t notice, but fast enough that others occasionally walking by my terminal would see a different color every time. I assure you, dear reader, this was the very height of wit at the time.

With the late 90s came the World Wide Web and the search engine, and the world got a lot smaller. For some reason, I was looking for how to set the X terminal background color again, this time searching the Internet instead of reading up in a reference book, and I stumbled on someone who wrote nearly exactly the same random-walk background color changer. My jaw dropped! I had found my long-lost identical twin brother! Of course, I e-mailed him to let him know. He was stoked, and we shot a couple funny e-mails back and forth riffing on the bizarre coincidence, and that was that.

Can you imagine this taking place today? It’s almost boringly obvious that if you search hard enough you’ll find another monkey on another typewriter writing exactly the same sentence as you. It doesn’t even bear mentioning. Heck, that’s the fundamental principle behind Codex / CoPilot – the code that you want to write has been already written so many times that it will emerge as the most statistically likely response from a giant pattern-matching, word-word completion neural net model.

Indeed, stop me if you’ve read this before.

ArcaOS: OS/2 Updated For The Modern World

For a certain subset of our readers, mentioning IBM’s OS/2 is likely to bring forth a pang of nostalgia, while for others it’s more likely to bring to mind meme images of rebooting ATM displays. Although OS/2 didn’t become the desktop giant that IBM had intended it to become, reports of its demise are very much premature. As [Michael MJD] covers in a recent video, ArcaOS is essentially the latest version of OS/2, under official license from IBM.

The initial release of ArcaOS was in 2017, and the most recent release was version 5.0.7 in December of 2021. What this gets you is an evolution of OS/2 Warp 4.52 that updates the operating system for modern day hardware, although [Michael]’s experiences with using USB and installing WordPerfect 5.2 end up being rather mixed. With IBM not intending to open source the OS any time soon, ArcaOS appears to be mostly aimed at companies and individuals who wish to keep running their old (OS/2) software on newer hardware, per the FAQ.

This is also reflected in the license cost should you wish to obtain a copy of ArcaOS, with a personal edition license costing $129. What this does get one over OS/2 Warp is SMP support, improved USB, audio and video support, along with an actual package manager (ANPM, based on RPM & Yum).

Would you splurge on an updated OS/2 OS like this, or is tinkering with a fully open source OS like Haiku (BeOS reborn) more your thing?

Continue reading “ArcaOS: OS/2 Updated For The Modern World”