classic hacks

2658 Articles

The 1980s Called – Asking For The Z80 Membership Card

September 15, 2017 by 36 Comments

The ’80’s and early ’90’s saw a huge proliferation of “personal” computers, spawning an army of hacker kids who would go on to hone their computing chops on 8-bit and 16-bit computers from brands such as Sinclair, Commodore, Acorn, Apple, Atari, Tandy/RadioShack and Texas Instruments. Fast forward to 2017, and Raspberry-Pi, BeagleBone and micro:bit computers reign supreme. But the old 8-bit and 16-bit computer systems can still teach us a lot.

[Lee Hart] has built the amazing Z80 Membership Card — a Z80 computer that fits in an Altoids tin. His design uses generic through hole parts mounted on a PCB with large pads, thick tracks and lots of track clearances, making assembly easy. Add to this his detailed documentation, where he weaves some amazing story telling, and it makes for a really enjoyable, nostalgic build. It makes you want to get under the hood and learn about computers all over again. The Z80 Membership Card features a Zilog Z80 microprocessor running at 4 MHz with 32k RAM and 32K EPROM, loaded with BASIC interpreter and monitor programs. A pair of 30-pin headers provide connections to power, I/O pins, data, address and control signals.

To accompany this board, he’s built a couple of companion “shield” boards. The Front Panel Card has a 16-key hex pad, 7-digit 7-segment LED display and Serial port. [Lee] has packed in a ton of features on the custom monitor ROM for the front panel card making it a versatile, two board, 8-bit system. Recently, he finished testing a third board in this series — a Serial/SD-Card/RAM shield which adds bank-switchable RAM and SD-card interface to provide “disk” storage. He’s managed to run a full CP/M-80 operating system on it using 64k of RAM. The two-board stack fits nicely in a regular Altoids tin. A fellow hacker who built the three-board sandwich found it too tall for the Altoids tin, and shared the design for a 3D printable enclosure.

[Lee] provides detailed documentation about the project on his blog with schematics, assembly instructions and code. He’s happy to answer questions from anyone who wants help building this computer. Do check out all of his other projects, a couple of which we’ve covered in the past. Check out Lee Hart’s Membership Card — a similar Altoids tin sized tribute to the 1802 CMOS chip and how he’s Anthropomorphizing Microprocessors.

Finally, we have to stress this once again — check out his Assembly Manuals [PDF, exhibit #1] — they are amazingly entertaining.

Thanks to [Matthew Kelley] who grabbed one of [Lee]’s kits and then tipped us off.

Hacked Headset Brings VR To The Commodore 64

September 14, 2017 by 6 Comments

The venerable Commodore 64 got a lot of people started in computers, and a hard core of aficionados keeps the platform very much alive to this day. But a C64 just doesn’t have the horsepower to do anything more than some retro 8-bit graphics games, right?

Not if [jim_64] has anything to say about it. He’s created a pair of virtual-reality goggles for the C64, and the results are pretty neat. Calling them VR is a bit of a stretch, since that would imply the headset is capable of sensing the wearer’s movements, which it’s not. With just a small LCD screen tucked into the slot normally occupied by a smartphone in the cheap VR goggles [jim64] used as a foundation for his build, this is really more of a 3D wearable display — so far. The display brings 3D-graphics to the C64, at least for the “Street Defender” game that [jim64] authored, a demo of which can be seen below. We’ll bet position sensing could be built into the goggles to control the game too. Even then it won’t be quite the immersive (and oft-times nauseating) experience that VR has become, but for a 35-year old platform, it’s not too shabby.

Looking for more C64 love? We’ve got a million of ’em — case mods, C64 laptops, tablets, even CPU upgrades.

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Relay Computer: You Can Hear It Think

September 11, 2017 by 29 Comments

Modern digital computers have complex instruction sets that runs on state-of-the-art ALUs which in turn are a consequence of miniaturized logic gates that are built with tiny transistors. These tiny transistors are essentially switches. You could imagine replacing with electromagnetic relays, and get what is called a relay computer. If you can imagine it, someone’s done it. In this case, [jhallenworld].

The Z3 was the first working programmable, fully automatic digital computer designed by Konrad Zuse. The board employs modern semiconductor devices such as memory and microcontrollers, however, the CPU is all relays. A hexadecimal keyboard allows for program entry and a segment display allows tracking the address and data. The program is piped into serial to the parallel decoder and fed to the CPU where the magic happens. Since the core is electromechanical it is possible to connect the output to peripherals such as a bell as demonstrated near the end of the video.

This project is a good balance of retro and modern to be useful to anyone interested in mechanical computers and should be a lot of fun for the geek kind. Hacking this computer to modify the instruction set should be equally rewarding and a good exercise for students of computing theory.

There is a SourceForge page dedicated to the project with the details on the project including the instruction set and architecture. Check out the video below and if you are inspired by the project, be sure to check out the [Clickity Clack]’a Videos on designing a relay computer bit by bit.

If You’re Going To Make A Model Engine, You Might As Well Make It A Merlin

September 11, 2017 by 42 Comments

It has been remarked before in more than one Hackaday post, that here are many communities like our own that exist in isolation and contain within them an astonishing level of hardware and engineering ability. We simply don’t see all the work done by the more engineering-driven and less accessory-driven end of the car modification scene, for example, because by and large we do not move in the same circles as them.

One such community in which projects displaying incredible levels of skill are the norm is the model making world. We may all have glued together a plastic kit of a Spitfire or a Mustang in our youth, but at the opposite end of the dial when it comes to models you will find craftsmanship that goes well beyond that you’d find in many high-end machine shops.

A project that demonstrates this in spades is [mayhugh1]’s quarter-scale model of a vintage Rolls-Royce Merlin V12 piston aero engine. This was the power plant that you would have found in many iconic Allied aircraft of the WW2 era, including the real-life Spitfires and all but the earliest of those Mustangs. And what makes the quarter-scale Merlin just that little bit more special, is that it runs. Just add fuel.

The build took place over a few years and many pages of a forum thread, and includes multiple blow-by-blow accounts, photos, and videos. It started with a set of commercial castings for the engine block, but their finishing and the manufacture of all other engine parts is done in the shop. In the final page or so we see the video we’ve placed below the break, of the finished engine in a test frame being run up on the bench, with a somewhat frightening unguarded airscrew attached to its front and waiting to decapitate an unwary cameraman. Sit down with a cup of your favourite beverage, and read the build from start to finish. We don’t think you’ll be disappointed.

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The Day Six Spaceships Landed In England

September 4, 2017 by 36 Comments

The BBC, as the British national broadcaster for so many decades, now finds itself also performing the function of keeper of a significant part of the collective national memory. Thus they have an unrivaled resource of quality film and audio recordings on hand for when they look back on the anniversary of a particular story, and the retrospectives they create from them can make for a particularly fascinating read.

This week has seen the fiftieth anniversary of a very unusual event, the day six flying saucers were found to have crash-landed in a straight line across the width of Southern England. It was as though a formation of invaders had entered the atmosphere in a manoeuvre gone wrong, and maintained their relative positions as they hurtled towards the unsuspecting countryside.

Except of course, there were no aliens, and there were no flying saucers. Instead there was a particularly resourceful group of apprentices from the Royal Aircraft Establishment at Farnborough, and the saucers were beautifully made fibreglass and metal creations. They contained electronic sound generators to give an alien-sounding beeping noise, and a fermenting mixture of flour and water for an alien-looking ectoplasmic goo should anybody decide to drill into them. The police were called and the RAF were scrambled, and a media frenzy occurred before finally the jolly hoaxters were unmasked. In those simpler times everyone had a good laugh and got on with their lives, while without a doubt now there would have been a full-blown terrorism scare and a biohazard alert over all that flour paste.

A Hackaday writer never admits her age, but this is a story that happened well before the arrival of this particular scribe. We salute and envy these 1960s pranksters, and hope that they went on to do great things. If you are a British resident you can see an accompanying TV report on their southern regional news programme, Inside Out, on BBC One South East and South today at 19:30 BST, or via BBC iPlayer should you miss it.

Flying saucer confectionery image: jo-h [CC BY 2.0].

A Floppy Drive For Apple’s Pippin

September 4, 2017 by 5 Comments

The Pippin was Apple’s first and last foray into gaming consoles. At its heart, the Pippin was a strange ‘multimedia device’ with a CD-ROM, the potential for Internet access, a few neat controllers, and the guts of a very bare-bones PowerPC Macintosh. Think of a cross between a 3DO and WebTV, and you’ll get an idea of what Apple was trying to build here.

The Pippin is rare, and that means the related accessories, ranging from magneto-optical drives to floppy drives, are incredibly hard to come by. Now, one of those peripherals isn’t rare anymore; [Pierre] has cloned the (passive) PCB that allows a Macintosh floppy drive to plug directly into the Pippin.

The expansion capabilities for the Pippin are locked away inside a PCI connector strategically located on the bottom of this set-top box. The official floppy drive accessory injection molded case, a standard Mac floppy drive, and a PCB. After finding one of these rare floppy drive accessories, [Pierre] simply took a meter to all the pins, traced out the circuit, and created a PCB with a PCI connector on one end, and 20-pin connector on the other. The PCB is shared on OSH Park if you want to check this out.

Although recreating this hardware was relatively easy, testing it was not. The first test used the Floppy Emu, a neat device that allows old Macs to read disk images off an SD card. This worked beautifully, but testing it out with a real floppy drive did not. Some disks simply didn’t work, although [Pierre] is chalking that one up to a problem with the USB floppy drive and a Mac running Sierra.

Repurposing Moving Coil Meters To Monitor Server Performance

August 31, 2017 by 11 Comments

Snazzy analog meters can lend a retro flair to almost any project, but these days they often seem to be retasked as indicators for completely different purposes than originally intended. That’s true for these Vu meters repurposed as gauges for a Raspberry Pi server, and we think the build log is as informative as the finished product is good-looking.

As [MrWunderbar] admits, the dancing needles of moving-coil meters lend hipster cred to a project, but getting his Vu meters to cooperate and display network utilization and disk I/O on his Raspberry Pi NAS server was no mean feat. His build log is full of nice details on how to measure the internal resistance of the meter and determine a proper series resistor. He also has a lengthy discussion of the relative merits of driving the meters using a PWM signal or using a DAC; in the end, [MrWunderbar] chose to go the DAC route, and the video below shows the desired rapid but smooth swings as disk and network usage change. He also goes into great depth on pulling usage parameters from psutil and parsing the results for display on the meters.

Looking for more analog meter goodness? We saw a similar CPU load meter a few months back, and there was this mash-up of Nixies and old meters for a solar energy CEO’s desk.

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