classic hacks

2801 Articles

Adding Persistent Memory And Ethernet To Vintage Arcade Machines

May 27, 2011 by 13 Comments

z80_bus_tapper

If you are a frequent reader, you are undoubtedly familiar with hacker [Sprite_tm]. He has been working with fellow members of the TkkrLab hackerspace to get things ready for their official grand opening on May 28th, and wrote in to share a project he recently completed to kick things off.

As part of their preparations, they have been stocking the joint with all sorts of hacker-friendly goodies including plenty of tools and Club Mate, as well as a vintage ‘1943’ arcade cabinet. The game is a group favorite, though every time the power is turned off, it loses all of the hard-earned high scores. [Sprite_tm] knew he could improve on the current paper-based score register, so he pulled the machine open to see what could be done.

He used an AVR to tap into the machine’s Z80 logic board, allowing him to read and write to the entirety of the game’s RAM whenever he pleased. This enabled him to keep tabs on the high scores, restoring them to memory whenever the machine is powered back on. The addition of the AVR also allowed him to add a TCP/IP interface, which is used to send high scores to Twitter whenever someone beats the previous record.

His modular bus tap can be used in all sorts of Z80-based hardware, so if you have some vintage equipment laying around, be sure to swing by his site for a more detailed look at the build process.

Hacked Phone Runs Zork, Gets Lamp

May 25, 2011 by 14 Comments

A few months ago, [Ulysses] had a project in mind that would run Zork on a TDD. Although it was a bit of a struggle getting the project ready in time for the Bay Area Maker’s Faire, the accompanying build blog tells us it was more than worth the effort.

After hooking up the guts of the phone to an Arduino Pro, A modem was modified so the acoustically coupled TDD could be interfaced. Although the TDD display is only one line, [Ulysses] is transmitting the text at only 45.5 baud, So even the slowest reader could keep up with the story. For running the actual code, initial attempts at using an Arduino Pro, and then Arduino Mega proved unsuccessful because of the limitations of sram in these AVRs. After discarding the idea of running Zork on an Arduino, the project was finished with a single board FitPC computer mounted inside the phone.

The code of the project runs Zork on a port of the Infocom Z-code Interpreter Program, or ZIP. A lot of interactive text adventures were put out in the Z-code format, so we’re guessing it would be trivial to have this project run Leather Goddesses of Phobos, or the amazing Hitchhiker’s Guide to the Galaxy. It’s a very nice project, and we could easily see ourselves sitting down with this project, a two liter bottle of Shasta, and an all-Rush mix tape on a Saturday night.

Shoehorning RS-232 Into A Minitel Terminal

May 22, 2011 by 30 Comments

In the early 80s, millions of terminals were handed out to French telephone subscribers. Nearly 9 million of these Minitel dumb terminals were in use at one time, and with that degree of ubiquity, we’re surprised we haven’t heard of them before. These boxes were usually connected to the outside world through their internal 1200bps modem, but [O. Blt] came up with this build (Google Translate link) so he could connect to a local machine with an RS-232 port.

After digging up the pinout for the Minitel’s DIN-8 port, [O. Blt] designed a little board around a MAX232 chip scavenged from an old motherboard. Of course there was a need to get the terminal to do something, so [O. Blt] used the Minitel as a display and remote control for Winamp. The project was successful, but not very useful – at 1200 bps, the refresh is very, very slow.

American readers may remember connecting to the Minitel network with their Apple ][s and C64s with CommunityLink, but this service was driven out of the market by the giants of pre-web dial-up, Prodigy and Compuserve. In any case, after seeing the AZERTY and alphabetic keyboard layouts of these old boxes gives us a feeling of nostalgia for a time before everything dealing with computers was standardized.

BAMF2011: Keyboards Built From Scratch

May 21, 2011 by 35 Comments

As the most direct interface between computer and programmer, keyboards can be a deeply personal, sometimes almost religious thing. Some find solace in their vintage IBM Model M, or luxurious leather keyboard, but maker [Carol Chen] took things into her own hands, quite literally. [Carol]’s Maker Faire exhibit has a half dozen specimens of interesting commercial tactile and ergonomic options…but [Chen]’s personal keyboard, where she commits to her work as a full-time coder, has been made to her own exacting specifications.

Continue reading “BAMF2011: Keyboards Built From Scratch” →

Arduino Magnetic Core Memory Shield

May 11, 2011 by 14 Comments

mag_core_memory

Magnetic core memory turns 60 years old today, and as a tribute [Ben North and Oliver Nash] have created a 32-bit magnetic core memory board for the Arduino.

Magnetic core memory was used from the 1950s through the 1970s, and provided a non-volatile means for storing data, as each magnetic core retained its orientation, even when the power was cut. While it sounds a lot like a modern hard drive, these devices were used in the same fashion as RAM is utilized today.

While the pair used surplus ferrite cores manufactured just before magnetic memory stopped being produced, they did allow themselves to use some modern components. Items such as transistors and logic gates were not available to the first magnetic core memory manufacturers, but the use of these items helped them complete the project in a reasonable amount of time.

Their final result is a magnetic memory board which can be used by any USB-enabled device and is reliable enough to withstand billions of read/write transactions.

BBC Covers An Old-school Hacker

April 29, 2011 by 19 Comments

Yesterday, the BBC posted an article on [Julian Skidmore]’s AVR-based homebrew computer.

[Julian]’s project uses an AVR and a derivative of Forth to recreate the capabilities of the 8-bit computers of yesteryear. With 8kB of RAM, [Julian] got a TV-out up and running, and even included code for a Lunar Lander game.

We’re happy for [Julian] getting some notoriety as an old-school solder monkey, but we’re wondering why the BBC is covering a project not unlike the something that could be seen on hackaday once a week. Could it be the first inkling of respect for the hacker and DIY community in the general public’s eye?

In any event, we love the initiative shown in [Julian]’s quote at the bottom of the BBC article: “Building the machine is a way to learn the essentials of what a computer is all about.” If you want to understand something, you’ve got to build it yourself. Truer words…

A Beginner’s Guide To LED Matrices

April 29, 2011 by 4 Comments

led_tutorial

[Rajendra Bhatt] wrote in to share a tutorial he put together demonstrating the basics of using LED dot matrix displays. While this subject might be old hat to many out there, his helpful walkthroughs are geared more towards beginners who are exploring various electronics concepts for the first time.

He explains the theory behind LED displays using a PIC-driven 5×7 matrix as an example. He discusses persistence of vision and how tricking the human eye can save you quite a bit of time and a whole lot of pins. Multiplexing is broken down into its most basic steps, which [Rajendra] illustrates by showing how a letter would be drawn on the LED display one column at a time. The use of a ULN2803A Darlington Array is also discussed, and he details why it is used when pulling the five columns of LEDs to ground.

The only portion of the tutorial we thought could be expanded upon was the programming section. While he does show how each letter of the alphabet can be displayed via a series of five hex values, he does not cover the “why” part of the process. Obviously while anyone familiar with binary and hex can figure it out in pretty short order, we think that it would be a great place to pause and expand the readers’ knowledge even more.

Overall it’s a useful tutorial, and most beginners would likely find it quite helpful.