Magnetic Bubble Memory Brought To Life On Heathkit

June 9, 2023 by Bryan Cockfield 11 Comments

There are all kinds of technology that appear through the ages that find immediate success, promise to revolutionize the world, but fade to obscurity almost as quickly. Things like the ZIP disk, RDRAM, the digital compact cassette, or even Nintendo’s VirtualBoy. Going even further back in time [smbaker] is taking a look a bubble memory, a technology that was so fast and cost-effective for its time that it could have been used as “universal” memory, combining storage and random-access memory into a single unit, but eventually other technological developments overshadowed its quirks.

[smbaker] is placing his magnetic bubble memory module to work in a Heathkit H8, an Intel 8080-based microcomputer from the the late 70s. The video goes into great detail on the theory of how these devices used moving “bubbles” of magnetism to store information and how these specific devices work before demonstrating the design and construction of a dedicated support card which hosts the module itself along with all of the necessary circuitry to allow it to communicate with the computer. From there he demonstrates booting the device using the bubble memory and performs several write and read actions using the module as a demonstration.

Eventually other technologies such as solid-state RAM and various hard disk drives caused the obsolescence of this technology, but it did hang on for a bit longer in industrial settings due to its ability to handle high vibrations and mechanical shocks, mostly thanks to the fact that they had no moving parts. Eventually things like Flash memory came around to put the final nail in the coffin for these types of memory modules, though. The Heathkit H8 is still a popular computer for retrocomputing enthusiasts nonetheless, and we’ve seen all kinds of different memory modules put to work in computers like these.

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Recreating An Analog TV Test Pattern

June 9, 2023 by Bryan Cockfield 25 Comments

While most countries have switched to digital broadcasting, and most broadcasts themselves have programming on 24/7 now, it’s hard to remember the ancient times of analog broadcasts that would eventually stop sometime late at night, displaying a test pattern instead of infomercials or reruns of an old sitcom. They were useful for various technical reasons including calibrating the analog signals. Some test patterns were simply camera feeds of physical cards, but if you wanted the most accurate and reliable test patterns you’d need a Philips pattern generator which created the pattern with hardware instead, and you can build your own now because the designs for these devices were recently open-sourced. Continue reading “Recreating An Analog TV Test Pattern” →

Using Excel To Manage A Commodore 64

June 8, 2023 by Bryan Cockfield 16 Comments

The “save” icon for plenty of modern computer programs, including Microsoft Office, still looks like a floppy disk, despite the fact that these have been effectively obsolete for well over a decade. As fewer and fewer people recognize what this icon represents, a challenge is growing for retrocomputing enthusiasts that rely on floppy disk technology to load any programs into their machines. For some older computers that often didn’t have hard disk drives at all, like the Commodore 64, it’s one of the few ways to load programs into computer memory. And, rather than maintaining an enormous collection of floppy discs, [RaspberryPioneer] built a way to load programs on a Commodore using Microsoft Excel instead.

The Excel sheet that manages this task uses Visual Basic for Applications (VBA), an event-driven programming language built into Office, to handle the library of applications for the Commodore (or Commodore-compatible clone) including D64, PRG, and T64 files. This also includes details about the software including original cover art and any notes the user needs to make about them. Using VBA, it also communicates to an attached Arduino, which is itself programmed to act as a disk drive for the Commodore. The neceessary configuration needed to interface with the Arduino is handled within the spreadsheet as well. Some additional hardware is needed to interface the Arduino to the Commodore’s communications port but as long as the Arduino is a 5V version and not a 3.3V one, this is fairly straightforward and the code for it can be found on its GitHub project page.

With all of that built right into Excel, and with an Arduino acting as the hard drive, this is one of the easiest ways we’ve seen to manage a large software library for a retrocomputer like the Commodore 64. Of course, emulating disk drives for older machines is not uncommon, but we like that this one can be much more dynamic and simplifies the transfer of files from a modern computer to a functionally obsolete one. One of the things we like about builds like this, or this custom Game Boy cartridge, is how easy it can be to get huge amounts of storage that the original users of these machines could have only dreamed of in their time.

Well Documented Code Helps Revive Decades-Old Commodore Project

June 7, 2023 by Bryan Cockfield 15 Comments

In the 1980s, [Mike] was working on his own RPG for the Commodore 64, inspired by dungeon crawlers of the era like Ultima IV and Telengard, both some of his favorites. The mechanics and gameplay were fairly revolutionary for the time, and [Mike] wanted to develop some of these ideas, especially the idea of line-of-sight, even further with his own game. But an illness, a stint in the military, and the rest of life since the 80s got in the way of finishing this project. This always nagged at him, so he finally dug out his decades-old project, dusted out his old Commodore and other antique equipment, and is hoping to finish it by 2024.

Luckily [Mike’s] younger self went to some extremes documenting the project, starting with a map he created which was inspired by Dungeons and Dragons. There are printed notes from a Commodore 64 printer, including all of the assembly instructions, augmented with his handwritten notes to explain how everything worked. He also has handwritten notes, including character set plans, disk sector use plans, menus, player commands, character stats, and equipment, all saved on paper. The early code was written using a machine language monitor since [Mike] didn’t know about the existence of assemblers at the time. Eventually, he discovered them and attempted to rebuild the code on a Commodore 128 and then an Amiga, but never got everything working together. There is some working code still on a floppy disk, but a lot of it doesn’t work together either.

While not quite finished yet, [Mike] has a well-thought-out plan for completing the build, involving aggregating all of the commented source code and doing quarterly sprints from here on out to attempt to get the project finished. We’re all excited to see how this project fares in the future. Beyond the huge scope of this pet project, we’d also suggest that this is an excellent example of thoroughly commenting one’s code to avoid having to solve mysteries or reinvent wheels when revisiting projects months (or decades) later. After all, self-documenting code doesn’t exist.

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Transform An Original Xbox Controller To A 360 Controller

June 7, 2023 by Bryan Cockfield 5 Comments

If you’re looking for a controller for your computer or mobile device, you could certainly do worse than one of the latest iterations of the Xbox pad. They might not be perfect, but they’re fairly well-made, not particularly expensive, use standard USB and Bluetooth interfaces, and even have decent support in the open-source community. So if you’re gaming on Linux or working on any other kind of retro gaming rig it’ll likely be plug-and-play.

This wasn’t the case with the first generation Xbox controller, though, and although its proprietary connector was actually using USB, the controller scheme wasn’t as open. This is [Tom]’s effort of upcycling his original Xbox controller to work indistinguishably from a stock Xbox 360 controller.

For those asking why anyone would want to do this, [Tom] is actually one of the few who enjoyed the original bulky Xbox “Duke” controller that released with the console in 2001. It wasn’t a popular choice in the larger gaming community and a year later Microsoft released a smaller version, but we all have our quirks. A Teensy 4.1 is attached to the end of the controller cable and acts as an intermediary to intercept the proprietary signalling coming from this controller and convert it into something usable. Since the controller doesn’t even show up as a standard USB HID device it took a little more sniffing of the protocol to decipher what was going on at all, but eventually some help was found within this other driver that gave [Tom] the clues he needed to get it working.

There were some other headaches to this project as well, especially since USB debugging USB connections while using USB isn’t exactly a streamlined process, but after a couple of breakthroughs the Teensy pass-through interface began working and [Tom] can use his controller of choice across multiple platforms now. If you’re looking to upgrade in other ways take a look at this build which seeks to recalibrate, rather than replace, an older Xbox controller experiencing drift on its analog control sticks.

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Harvesting Rechargeable Batteries From Single-Use Devices

June 7, 2023 by Bryan Cockfield 64 Comments

The price of lithium batteries has plummeted in recent years as various manufacturers scale up production and other construction and process improvements are found. This is a good thing if you’re an EV manufacturer, but can be problematic if you’re managing something like a landfill and find that the price has fallen so low that rechargeable lithium batteries are showing up in the waste stream in single-use devices. Unlike alkaline batteries, these batteries can explode if not handled properly, meaning that steps to make sure they’re disposed of properly are much more important. [Becky] found these batteries in single-use disposable vape pens and so set about putting them to better use rather than simply throwing them away.

While she doesn’t use the devices herself, she was able to source a bunch of used ones locally from various buy-nothing groups. Disassembling the small vape pens is fairly straightforward, but care needed to be taken to avoid contacting some of the chemical residue inside of the devices. After cleaning the batteries, most of the rest of the device is discarded. The batteries are small but capable and made of various lithium chemistries, which means that most need support from a charging circuit before being used in any other projects. Some of the larger units do have charging circuitry, though, but often it’s little more than a few transistors which means that it might be best for peace-of-mind to deploy a trusted charging solution anyway.

While we have seen projects repurposing 18650 cells from various battery packs like power tools and older laptops, it’s not too far of a leap to find out that the same theory can be applied to these smaller cells. The only truly surprising thing is that these batteries are included in single-use devices at all, and perhaps also that there are few or no regulations limiting the sale of devices with lithium batteries that are clearly intended to be thrown away when they really should be getting recycled.

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RetroPie, Without The Pi

June 6, 2023 by Bryan Cockfield 24 Comments

The smart television is an interesting idea in theory. Rather than having the cable or satellite company control all of the content, a small computer is included in the television itself to host and control various streaming clients and other services. Assuming you have control of the software running on the computer, and assuming it isn’t turned into a glorified targeted advertising machine, this can revolutionize the way televisions are used. It’s even possible to turn a standard television into a smart TV with various Android devices, and it turns out there’s a lot more you can do with these smart TV contraptions as well.

With most of these devices, a Linux environment is included running on top of an ARM platform. If that sounds similar to the Raspberry Pi, it turns out that a lot of these old Android TV sets are quite capable of doing almost everything that a Raspberry Pi can do, with the major exception of GPIO. That’s exactly what [Timax] is doing here, but he notes that one of the major hurdles is the vast variety of hardware configurations found on these devices. Essentially you’d have to order one and hope that you can find all the drivers and software to get into a usable Linux environment. But if you get lucky, these devices can be more powerful than a Pi and also be found for a much lower price.

He’s using one of these to run RetroPie, which actually turned out to be much easier than installing a more general-purpose Linux distribution and then running various emulation software piecemeal. It will take some configuration tinkering get everything working properly but with [Timax] providing this documentation it should be a lot easier to find compatible hardware and choose working software from the get-go. He also made some improvements on his hardware to improve cooling, but for older emulation this might not be strictly necessary. As he notes in his video, it’s a great way of making use of a piece of electronics which might otherwise be simply thrown out.

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