A Handy Guide To The Humble BBS

November 29, 2022 by Bryan Cockfield 35 Comments

Some of us who’ve been online since the early days fondly remember the web of yore — with its flashing banners, wildly distracting backgrounds, and automatic side-scrolling text. But there was a time before the worldwide web and the Internet as we recognize it today, and the way of communicating in this before-time was through Bulletin Board Systems, or BBS. There are still some who can cite this deep magic today, and this page is perhaps the definitive guide to this style of retrocomputing.

This how-to is managed by [Blake.Patterson] who is using a wide variety of antique machines and some modern hardware in order to access the BBSes still in service. He notes in this guide that it’s possible to use telnet and a modern computer to access them, but using something like an Amiga or Atari will give you the full experience. There are some tools that convert the telephone modem signals from that original hardware to something that modern networking equipment can understand, and while the experience might be slightly faster as a result, it does seem to preserve the nostalgia factor quite well.

For those looking for more specific guides, we’ve featured [Blake]’s work a few times in the past, once with an antique Epson PX-8 laptop and again with a modern ESP8266. It doesn’t take much computing power to get connected to these old services, so grab whatever you can and start BBSing!

MikroLeo, A 4-Bit Retro Learning Platform

November 27, 2022 by Dave Rowntree 24 Comments

MikroLeo is a discrete TTL logic-based microcomputer intended for educational purposes created by [Edson Junior Acordi], an Electronics Professor at the Brazilian Federal Institute of Paraná, Brazil. The 4-bit CPU has a Harvard RISC architecture built entirely from 74HCT series logic mounted on a two-sided PCB using only through-hole parts. With 2K words of instruction RAM and 2K words of addressable RAM, the CPU has a similar resource level to comparable machines of old, giving students a feel for how to work within tight constraints.

Simulation of the circuit is possible with digital, with the dedicated PCB designed with KiCAD, so there should be enough there to get cracking with it. Four 4-bit IO ports make interfacing easy, with dedicated INput and OUTput instructions for the purpose. An assembler, compiler, and emulator are all being worked on (as far as we can tell) so keep an eye out for that, if this project is of interest to you.

We like computers a bit around these parts, the “hackier” and weirder the better. Even just in the 4-bit retro space, we’ve seen so many, from those built around ancient ALU chips to those built from discrete transistors and diodes, but you don’t need to go down that road, an emulation platform can scratch that retro itch, without the same level of pain.

A Homemade Tube Amplifier Featuring Homemade Tubes

October 27, 2022 by Dan Maloney 23 Comments

With the wealth of cheap and highly integrated audio amplifier modules on the market today, it takes a special dedication to roll your own from parts. Especially when those parts include vacuum tubes, and doubly so when you make the vacuum tubes from scratch too.

Now, we get it — some readers are going to find it hard to invest an hour in watching [jdflyback] make a pair of triodes to build his amplifier. But really, you’ve got to check this out. Making vacuum tubes with all the proper equipment — glassblower’s lathe, various kinds of oxy-fuel torches, all the right hand tools — is hard enough. But when your lathe is a cordless drill, and you’re using a spot welder that looks like it’s cobbled together from junk, your tube-making game gets a lot harder. Given all that, you’d expect the tubes to look a lot rougher than they are, but even with plain tungsten wire heaters and grids made from thick copper wire, they actually work pretty well. Sure, the heaters glow as bright as light bulbs, but that’s all part of the charm.

Speaking of charm, we just love the amp these tubes went into. Built in 1920s breadboard-style, the features some beautiful vintage mica capacitors and wirewound resistors, plus a variable resistor the likes of which we’ve never seen. The one nod to modernity is the clever use of doorbell transformers, one for a choke and one for the speaker transformer. They don’t sound great, but there’s no doubt they work.

We may have seen other homemade vacuum tubes before — we even recently featured a DIY X-ray tube — but there’s something about [jdflyback]’s tubes that really gets us going.

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Clover Computer: A Modern Z8000 CP/M Machine

August 21, 2022 by Chris Lott 20 Comments

Seeing some old Zilog 16-bit chips on eBay recently, [Scott Baker] was curious enough to snap them up and build himself a Z8000 computer. It started as a two-board solution, then he added a display module. Instead of layering the boards vertically à la a PC/104 stack, [Scott] decided to build them flat. His first backplane was triangular, but he opted for a square to accommodate one more expansion board in the future. The assembled contraption resembles a clover, hence the name Clover Computer.

The Z8000 was Zilog’s first 16-bit microprocessor, introduced in 1979. It was not hugely popular for a variety of reasons (the Z8000 Wikipedia article has some interesting details). The Z8000 was eclipsed in the marketplace by Intel’s 8088 and Motorola’s 32-bit 68000. One interesting point is that the Z8000 did not use microcode, and as a result, its transistor count was significantly less than its contemporaries. The Z8000 was used in some military applications, and despite its limited commercial success, it continued to be available from Zilog and licensed second sources up until 2012.

[Scott]’s design splits the system into a CPU board, a memory and serial board, and a display board. Along the way, he learns 1980’s era tricks from the Olivetti M20, one of the few computer systems designed around the Z8000. He also manages to find a recent Z8000 implementation of CP/M by GitHub user [4sun5bu], which [Scott] forked and adapted to his project (see project repo here). He succeeds in getting everything working, and ports a monitor, Tiny Basic, and Zork.

Check out his project write-up introductory link, and see it in action in the video below the break. Did you ever use or encounter the Z8000? Let us know in the comments!

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New OS For Commodore 64 Adds Modern Features

July 28, 2022 by Bryan Cockfield 45 Comments

The Commodore 64 was a revolutionary computer for its day and age. After four decades, though, it gets harder and harder to use these computers for anything more than educational or hobby electronics projects. [Gregory Nacu] is fiercly determined to challenge this idea, though, and has gone to great extremes to make this hardware still relevant in the modern age by writing a completely new operating system for the Commodore machines.

Known as C64OS, it squeezes everything it can out of the 8 bit processor and 64 kB of memory. The new OS includes switchable desktop workspaces, a windowing system, draggable icons, a Mac-style menu bar at the top, and drop-down menus for the icons (known as aliases in the demonstrations). The filesystem is largely revamped as well and enables a more modern directory system to be used. There are still some limitations like a screen resolution of 320×200 pixels and a fixed color palette which only allows for a handful of colors, but this OS might give Windows 3.1 a run for its money.

The project is still being actively developed but it has come a long way into a fairly usable state. It can be run on original hardware as well as long as you have a method of getting the image to the antique machine somehow. If not, the OS can likely run on any number of C64 emulators we’ve featured in the past.

Thanks to [Stephen] for the tip!

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Building A Serial Bus To Save An Old Hard Drive

June 28, 2022 by Bryan Cockfield 67 Comments

Universal Serial Bus has been the de facto standard for sending information to and from computer peripherals for almost two decades, but despite the word “universal” in the name this wasn’t always the case. Plenty of competing standards, including USB, existed in the computing world in the decades before it came to dominance, and if you’re trying to recover data from a computer without USB you might have to get creative with how it’s done.

[Ben] recently came across a 80486 with this problem, so he had to get creative to recover the contents of the drive. He calls it the “lunchbox” computer due to its form factor, and while it doesn’t have USB it does have a tried-and-trusted serial port to communicate with other computers. [Ben] wrote up a piece of software for both the receiving computer and the sending computer in order to copy the drive sectors one by one across a serial link to a standalone computer running Windows XP, and was able to recover the contents of the drive that way instead.

All of the code [Ben] wrote is available on his GitHub page for anyone looking to boot up a 30-year-old computer again. While it might sound uncommon, computers of this vintage are still around running things like CNC machines or old mainframes.

Faux-Retro “Tape” Player Runs On ESP32 And 80s Vibes

June 23, 2022 by Tom Nardi 31 Comments

At first glance, this gorgeous retro-styled audio player built by [Max Kern] could absolutely pass for the genuine article. But then you take a closer look and realize that the “tape” it’s playing is actually an animation running on a 320 x 240 IPS display, and the Play and Rewind buttons on the front aren’t the chunky electromechanical affairs of yesteryear but actually cleverly repurposed MX keyboard switches.

By now you’re probably realizing that this player is quite a bit smaller than you first imagined, which in turn, means that it even its case is a modern fabrication. While it might perfectly encapsulate the look and feel of a piece of 1980s consumer electronics, it was squirted out on a thoroughly modern desktop 3D printer.

Even so, [Max] made sure to include draft angles in the CAD design and and a distinctive separation line so the case looked like it was injection molded. Following similar logic, he decided against using a modern rechargeable battery pack to power the electronics, opting instead for a more era-appropriate set of AA batteries.

In terms of hardware, the custom PCB is home to an ESP32 WROOM, a MAX98357A I2S audio amplifier, a FT231XS USB-to-serial chip, with enough passives and regulators to keep them all well fed and happy. The ESP32 has more than enough computational horsepower to chew through MP3 files, which are conveniently loaded via an SD slot built into the side of the player. As the player was actually intended for audio books, onboard playback is limited to a mono speaker; though there is a 3.5 mm audio jack to plug in a pair of headphones for when the built-in speaker isn’t up to the task.

Check out the video after the break to see how the player is assembled, as well as a demonstration of its simple three-button user interface. It looks like a joy to use, though the lack of fast forward and rewind sound effects took us a bit by surprise given the otherwise impeccable attention to detail. We’ll assume there’s some technical limitation that makes this particularly difficult to implement, and that their absence is currently keeping [Max] up at night.

As impressive as the final product is, we can’t say it’s a surprise. Frankly, we wouldn’t expect anything less from [Max] at this point. His adaptive OLED macro pad wowed us back in 2020, and his ZeroBot is still one of the slickest designs for a DIY two-wheeled robots we’ve ever seen.

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