classic hacks

2768 Articles

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.

Continue reading “If You’re Going To Make A Model Engine, You Might As Well Make It A Merlin” →

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.

Continue reading “Repurposing Moving Coil Meters To Monitor Server Performance” →

Wood Finish From Old Records

August 23, 2017 by 36 Comments

Next time you’re working on a project that needs a durable wood finish, don’t grab the polyurethane. Follow [Victor Ola’s] advice and raid your grandparent’s record cabinet for some old 78 records. Modern records are made from vinyl. The stiff, brittle old 78’s from the 1960’s and earlier were made from shellac. Shellac is a natural material secreted by the female lac bug. It can be thought of as a natural form of plastic and was used as such for years until man-made plastics became commodity items.

Older 78 RPM phonograph albums are usually made entirely from shellac. [Victor] started by taking a few old cracked records and pulverizing them with a hammer. The shellac crumbs were then poured into a mason jar along with some isopropyl alcohol. The alcohol dissolves the shellac, creating a thick goo. More alcohol will thin the slurry down to a paintable consistency. The mixture is then ready to be painted on any wood surface. Wiping off the excess will reveal the wood grain.

Shellac is normally amber in color. Records are black because carbon is added to the mix. This makes the shellac stain dark and makes it a flat finish. While it would be fine to leave it this way, [Victor] added a coat of lacquer over his shellac stain to achieve a glossy finish on his upcycled gramophone.

If you’re getting into woodworking, don’t worry – anyone can do it. Just make sure you have sharp tools.

Continue reading “Wood Finish From Old Records” →

This 6502 Computer Project Is A Work Of Art

August 21, 2017 by 30 Comments

If you were a home constructor in the 8-bit era, the chances are that if you built a microcomputer system you would have ended up with a bare printed circuit board and a terminal. If you were on a budget you might have had a piece of stripboard as well, or maybe even wire-wrap. Beautiful cases were out of reach, they came with expensive commercial computers that were not the preserve of impoverished hobbyists.

Constructing an 8-bit machine in 2017 is a much easier process, there are many more options at your disposal. There is no need to make a bare PCB when you have a 3D printer, and this is demonstrated perfectly by [Dirk Grappendorf]’s 6502 computer project. He’s built from scratch an entire 6502 system, with a text LCD display, and housed it in a case with a keyboard that would put to shame all but the most expensive commercial machines from back in the day.

But this is more than just a hobby project thrown together that just happens to have a nice case, he’s gone the extra mile to the extent that this is professional enough that it could have been a product. If you’d been offered [Dirk]’s machine in 1980 alongside the competitors from Apple and Commodore, you’d certainly have given it some consideration.

We’ve seen retrocomputers too numerous to mention on these pages over the years, so if they are your thing perhaps it’s time to draw your attention to our VCF West reports, and to our reviews of computer museums in Germany, and Cambridge or Bletchley, UK.

Thanks [Colin] for the tip.