The Bendix G-15 Runs 75,000 Lines Of Code

There’s a Blue Bendix in Texas, and thanks to [Usagi Electric] it’s the oldest operating computer in North America.  The Bendix G-15, a vacuum tube computer originally released in 1956, is now booting, and running code from paper tape. [David, aka Usagi] received the G-15 about a year ago from The System Source museum. The goal was to get the computer running so museum patrons could interact with a real tube computer. We’ve been following along since the project began.

[Usagi’s] latest G-15 video covers the last few problems on the road to running code. The biggest hurdle was the fact that the system wasn’t responding properly to the GO button on the typewriter. [Usagi] was able to isolate the issue down to a flip flop and then to a particular signal on an AND gate — the RC signal. The gate appeared to be bad, but swapping the entire circuit card multiple times had no effect. Something else had to be going on.

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Hackaday Links: December 15, 2024

It looks like we won’t have Cruise to kick around in this space anymore with the news that General Motors is pulling the plug on its woe-beset robotaxi project. Cruise, which GM acquired in 2016, fielded autonomous vehicles in various test markets, but the fleet racked up enough high-profile mishaps (first item) for California regulators to shut down test programs in the state last year. The inevitable layoffs ensued, and GM is now killing off its efforts to build robotaxis to concentrate on incorporating the Cruise technology into its “Super Cruise” suite of driver-assistance features for its full line of cars and trucks. We feel like this might be a tacit admission that surmounting the problems of fully autonomous driving is just too hard a nut to crack profitably with current technology, since Super Cruise uses eye-tracking cameras to make sure the driver is paying attention to the road ahead when automation features are engaged. Basically, GM is admitting there still needs to be meat in the seat, at least for now.

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A Look Back At Google’s 2015 Chromecast

Google’s Chromecast was first released in 2013, with a more sophisticated follow-up in 2015, which saw itself joined by the Chromecast Audio dongle. The device went through an additional two hardware generations before the entire line of products was discontinued earlier this year in favor of Google TV.

Marvell's Armada 88DE3006 dual-core Cortex-A7 powers the second-generation ChromeCast. (Credit: Brian Dipert, EDN)
Marvell’s Armada 88DE3006 dual-core Cortex-A7 powers the second-generation Chromecast. (Credit: Brian Dipert, EDN)

In addition to collecting each generation of Chromecast, [Brian Dipert] over at EDN looked back on this second-generation dongle from 2015 while also digging into the guts of a well-used example that got picked up used.

While not having any of the fascinating legacy features of the 2nd-generation Ultra in his collection that came with the Stadia gaming controller, it defines basically everything that Chromecast dongles were about: a simple dongle with a HDMI & USB connector that you plugged into a display that you wanted to show streaming content on. The teardown is mostly similar to the 2015-era teardown by iFixit, who incidentally decided not to assign any repairability score, for obvious reasons.

Most interesting about this second-generation Chromecast is that the hardware supported Bluetooth, but that this wasn’t enabled until a few years later, presumably to fix the wonky new device setup procedure that would be replaced with a new procedure via the Google Home app.

While Google’s attention has moved on to newer devices, the Chromecast isn’t dead — the dongles in the wild still work, and the protocol is supported by Google TV and many ‘smart’ appliances including TVs and multimedia receivers.

Large gears on a bridge in Geneva, Switzerland

Gear Up: A 15-Minute Intro On Involute Gears

If you’re into CNC machining, mechanical tinkering, or just love a good engineering rabbit hole, you’re in for a treat. Substack’s [lcamtuf] has written a quick yet insightful 15-minute introduction to involute gears that’s as informative as it is accessible. You can find the full article here. Compared to Hackaday’s more in-depth exploration in their Mechanisms series over the years, this piece is a beginner-friendly gateway into the fascinating world of gear design.

Involute gears aren’t just pretty spirals. Their unique geometry minimizes friction and vibration, keeps rotational speeds steady, and ensures smooth torque transfer—no snags, no skips. As [lcamtuf] points out, the secret sauce lies in their design, which can’t be eyeballed. By simulating the meshing process between a gear and a rack (think infinite gear), you can create the smooth, rolling movement we take for granted in everything from cars to coffee grinders.

From pressure angles to undercutting woes, [lcamtuf] explores why small design tweaks matter. The pièce de résistance? Profile-shifted gears—a genius hack for stronger teeth in low-tooth-count designs.

Whether you’re into the theory behind gear ratios, or in need of a nifty tool to cut them at home, Hackaday has got you covered. Inspired?

Apple Forces The Signing Of Applications In MacOS Sequoia 15.1

The dialogue that greets you when you try to open an unsigned application in MacOS Sequoia 15.1.

Many MacOS users are probably used by now to the annoyance that comes with unsigned applications, as they require a few extra steps to launch them. This feature is called Gatekeeper and checks for an Apple Developer ID certificate. Starting with MacOS Sequoia 15, the easy bypassing of this feature with e.g. holding Control when clicking the application icon is now no longer an option, with version 15.1 disabling ways to bypass this completely. Not unsurprisingly, this change has caught especially users of open source software like OpenSCAD by surprise, as evidenced by a range of forum posts and GitHub tickets.

The issue of having to sign applications you run on MacOS has been a longstanding point of contention, with HomeBrew applications affected and the looming threat for applications sourced from elsewhere, with OpenSCAD issue ticket #880 from 2014 covering the saga for one OSS project. Now it would seem that to distribute MacOS software you need to have an Apple Developer Program membership, costing $99/year.

So far it appears that this forcing is deliberate on Apple’s side, with the FOSS community still sorting through possible workarounds and the full impact.

Thanks to [Robert Piston] for the tip.

IPhone 15 Gets Dual SIM Through FPC Patch

It can often feel like modern devices are less hackable than their thicker and far less integrated predecessors, but perhaps it’s just that our techniques need to catch up. Here’s an outstanding hack that adds a dual SIM slot to a US-sold eSIM iPhone 15/15 Pro, while preserving its exclusive mmwave module. No doubt, making use of the boardview files and schematics, it shows us that smartphone modding isn’t dead — it could be that we need to acknowledge the new tools we now have at our disposal.

When different hardware features are region-locked, sometimes you want to get the best of both worlds. This mod lets you go the entire length seamlessly, no bodges. It uses a lovely looking flexible printed circuit (FPC) patch board to tap into a debug header with SIM slot signals, and provides a customized Li-ion pouch cell with a cutout for the SIM slot. There’s just the small matter of using a CNC mill to make a cutout in the case where the SIM slot will go, and you’ll need to cut a buried trace to disable the eSIM module. Hey, we mentioned our skills needed to catch up, right? From there, it appears that iOS recognizes the new two SIM slots seamlessly.

The video is impressive and absolutely worth a watch if modding is your passion, and if you have a suitable CNC and a soldering iron, you can likely install this mod for yourself. Of course, you lose some things, like waterproofing, the eSIM feature, and your warranty. However, nothing could detract from this being a fully functional modkit for a modern-day phone, an inspiration for us all. Now, perhaps one of us can take a look at building a mod helping us do parts transplants between phones, parts pairing be damned.

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Reviving A 15-Year Old Asus EeePC With Modern MX Linux

Welcome back to 2010 and the Asus eeePC Netbook, Seashell series. (Credit: Igor Ljubuncic)
Welcome back to 2010 and the Asus eeePC Netbook, Seashell series. (Credit: Igor Ljubuncic)

It’s often said these days that computers don’t become outdated nearly as quickly as they did in the past, with even a decade-old computer still more than capable of handling daily tasks for the average person. Testing that theory, [Igor Ljubuncic] revisited the Asus eeePC which he purchased back in 2010. Although it’s not specified exactly which model it is, it features an Intel Atom N450 (1 core, 2 threads) running at 1.67 GHz, 1 GB of 667 MHz DDR2 and a 250 GB HDD, all falling into that ultra-portable, 10.1″ Netbook category.

When new, the netbook came with Windows 7 Starter Edition, which [Igor] replaced with Ubuntu Netbook Remix 10.04, which was its own adventure, but the netbook worked well and got dragged around the world on work and leisure assignments. With increasingly bloated updates, Ubuntu got replaced by MX Linux 18, which improved matters, but with the little CPU struggling more and more, [Igor] retired the netbook in 2019. That is, until reviving it recently.

Upon booting, the CMOS battery was of course empty, but the system happily continued booting into MX Linux. The Debian update repositories were of course gone, but changing these to the archive version allowed for some (very old) updates. This raised the question of whether modern Linux would even run on this ancient Atom CPU, the answer of which turned out to be a resounding ‘yes’, as MX Linux still offers 32-bit builds of its most recent releases. A 15 minute upgrade process later, and a 2 minute boot later, the system was running a Linux 6.1 kernel with Xfce desktop.

As for the performance, it’s rather what you expect, with video playback topping out at 480p (on the 1024×600 display) and applications like Firefox lacking the compact density mode, wasting a lot of screen space. Amazingly the original battery seems to still deliver about half the runtime it did when new. All of which is to say that yes, even a ‘low-end’ 2010-era netbook can still be a very usable system in 2024, with a modern OS.