classic hacks

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The Almost Useful Machine

June 11, 2016 by 26 Comments

[Alex] is no stranger to making machines of negligible utility. A few years ago he made the Almost Useless Machine, a solar-powered system that cuts through a 20mm dowel rod while you wait (and wait, and wait). Enamored by the internet’s bevy of powered hacksaws, he sought to build a sturdier version that’s a little more useful. Approximately five months of free time later, he had the Almost Useful Machine.

It runs on a wiper motor and a recycled power supply from a notebook computer. [Alex] rolled his own board for controlling the motor with an ATtiny25. The circuit turns potentiometer movement into PWM, which controls the motor through a MOSFET. After the cut is finished, an endstop microswitch  immediately cuts the motor.

Every bit of the chassis is aluminum that [Alex] machined by hand. Don’t have that kind of setup? How about a powered hacksaw with a 3D-printed linkage? Make the jump to see it in action, and stick around for the two-part time-lapse build video.

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An Atari ST Rises From The Ashes

June 9, 2016 by 19 Comments

We’ve all made rash and impulsive online purchasing decisions at times. For [Drygol] the moment came when he was alerted to an Atari 1040STe 16-bit home computer with matching monitor at a very advantageous price.

Unfortunately for him, the couriers were less than careful with his new toy. What arrived was definitely an ST, but new STs didn’t arrive in so many pieces of broken ABS. Still, at least the computer worked, so there followed an epic of case repair at the end of which lay a very tidy example of an ST.

He did have one lucky break, the seller had carefully wrapped everything in shrink-wrap so no fragments had escaped. So carefully applying acetone to stick the ABS together he set to work on assembling his unexpected 3D jigsaw puzzle. The result needed a bit of filler and some sanding, but when coupled with a coat of grey paint started to look very like an ST case that had just left the factory. Adding  modern SD card and USB/Ethernet interfaces to the finished computer delivered a rather useful machine as you can see in the video below the break.
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High Voltage Please, But Don’t Forget The Current

June 8, 2016 by 30 Comments

In high voltage applications involving tens of thousands of volts, too often people think about the high voltage needed but don’t consider the current. This is especially so when part of the circuit that the charge travels through is an air gap, and the charge is in the form of ions. That’s a far cry from electrons flowing in copper wire or moving through resistors.

Consider the lifter. The lifter is a fun, lightweight flying machine. It consists of a thin wire and an aluminum foil skirt separated by an air gap. Apply 25kV volts across that air gap and it lifts into the air.

Lifter flying with high voltage power supply
Lifter parts

So you’d think that the small handheld Van de Graaff generator pictured below, that’s capable of 80kV, could power the lifter. However, like many high voltage applications, the lifter works by ionizing air, in this case ionizing air surrounding the thin wire resulting in a bluish corona. That sets off a chain of events that produces a downward flowing jet of air, commonly called ion wind, lifting the lifter upward.

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Metalized Gift Wrap Saves A Classic Keyboard

June 8, 2016 by 16 Comments

What do you do when you decide that running CP/M on a Commodore 128 with a 5.25″ drive “Isn’t CP/M enough”? If you are [FozzTexx], you reach for your trusty TRS-80 Model II, with its much more CP/M-appropriate 8″ drive.

There was one small snag with the TRS-80 though, its keyboard didn’t work. It’s a capacitive device, meaning that instead of each key activating a switch, it contains a capacitive sensor activated by a piece of aluminized Mylar film on a piece of foam. Nearly four decades of decay had left the foam in [FozzTexx]’s example sadly deflated, leaving the keys unable to perform. Not a problem, he cast around for modern alternatives and crafted replacements from a combination of foam weather strip and metalized gift wrap.

Care had to be taken to ensure that the non-metalized side of the gift wrap faced the capacitive sensor pads, and that the weather strip used had the right thickness to adequately fill the gap. But the result was a keyboard that worked, and for a lot less outlay and effort than he’d expected. We would guess that this will be a very useful technique for owners of other period machines with similar keyboards.

What is CP/M, I hear you ask? Before there was Linux, Windows, and MacOS, there was DOS, and before DOS, there was CP/M. In the 1970s this was the go-to desktop operating system, running on machines powered by Intel’s 8080 and its derivatives like the Zilog Z80 in the TRS-80. When IBM needed an OS for their new PC they initially courted CP/M creators Digital Research, but eventually they hired a small software company called Microsoft instead, and the rest is history. Digital Research continued producing CP/M and its derivatives, as well as an MS-DOS clone and the GEM GUI that may be familiar to Atari ST owners, but were eventually absorbed into Novell in the 1990s.

We’ve featured a few capacitive keyboards here at Hackaday before, including this similar repair to a Compaq from the 1980s, and this look at a classic IBM terminal keyboard.

FPGA-and-Pi Colossus Smashes Your Codes!

June 8, 2016 by 6 Comments

If it were sixty years ago, and you were trying to keep a secret, you’d be justifiably glad that [Ben North] hadn’t traveled back in time with his Raspberry-Pi-and-FPGA code-breaking machine.

We’ve seen a lot of Enigma builds here at Hackaday — the World War II era encryption machine captured our readers’ imaginations. But perhaps the more important machines to come out of cryptanalysis during that era were Turing’s electromechanical Bombe, because it cracked Enigma, and the vacuum-tube-based Colossus, because it is one of the first programmable electronic digital computers.

[Ben]’s build combines his explorations into old-school cryptanalysis with a practical learning project for FPGAs. If you’re interested in either of the above, give it a look. You can start out with his Python implementations of Colossus to get your foot in the door, and then move on to his GitHub repository for the FPGA nitty-gritty.

It’s also a cool example of a use for the XuLA2 FPGA board and its companion StickIt board that plug straight into a Raspberry Pi for programming and support. We haven’t seen many projects using these since we first heard about them in 2012. This VirtualBoy hack jumped out at us, however. It looks like a nice platform. Anyone else out there using one?

One Man’s Awesome Collection Of Projects Done Over A Lifetime

June 7, 2016 by 21 Comments

[Robert Glaser] kept all his projects, all of them, from the 1960s to now. What results is a collection so pure we feel an historian should stop by his house, if anything, to investigate the long-term effects of the knack.

He starts with an opaque projector he built in the third grade, which puts it at 1963. Next is an, “idiot box,” which looks suspiciously like “the Internet”, but is actually a few relaxation oscillators lighting up neon bulbs. After that, the condition really sets in, but luckily he’s gone as far as to catalog them all chronologically.

We especially enjoyed the computer projects. It starts with his experiences with punch cards in high school. He would hand-write his code and then give it to the punch card ladies who would punch them out. Once a week, a school-bus would take the class to the county’s computer, and they’d get to run their code. In university he got to experience the onset of UNIX, C, and even used an analog computer for actual work.

There’s so much to read, and it’s all good. There’s a section on Ham radio, and a very interesting section on the start-up and eventual demise of a telecom business. Thanks to reader, [Itay Ramot], for the tip!

The World’s Supply Of DB-19 Connectors

June 6, 2016 by 45 Comments

[Steve] over at Big Mess O’ Wires has a very, very niche product. It’s the Floppy Emu, a hard disk emulator for the Apple II, Lisa, and very old Macs. The Floppy Emu takes data stored on an SD card and presents it to these classic computers through a contemporary connector, the venerable DB-19. This connector is in the same family as the familiar DB-25 parallel port, DE-9 serial port and the old DA-15 joystick port, but there’s something very special about the DB-19 connector – nobody makes it anymore, and no surplus electronics store has any in stock. They’re unobtanium, and when you’re making a product built around this connector, you’re going to have a few problems.

Those problems have come to a head over the past year, but getting a few thousand DB-19 connectors manufactured has always seemed just out of reach. It would be a five-figure investment for a very niche product, and [Steve] would have to find someone to make the connectors.

The world’s shortage of DB-19 connectors is no more. After chatting up a few people in the NeXT and Atari communities, [Steve] set up a group buy and manufactured the first batch of DB-19 connectors in recent memory. The world’s supply of DB-19 connectors, all 10,000 of them, is now in [Steve]’s living room.

The process of manufacturing ten thousand DB-19 connectors actually wasn’t that hard for [Steve]. Over the past year, he’s reached out to manufacturers to get a quote, and he still had those numbers in his rolodex. The only problem was finding an engineering drawing of a DB-19 connector and transferring a large amount of money to Hong Kong. The drawing was easy enough, as datasheets sometimes last longer than the parts they describe. Transferring the money over to the manufacturer meant convincing a bank manager there is not a Nigerian prince in Hong Kong and thirty minutes of paperwork.

After a few months, a round of prototyping, and a trip through customs, the world’s supply of DB-19 connectors finally landed on [Steve]’s porch. He still needs to ship them out to the NeXT and Atari folk who participated in the group buy, but the great shortage of DB-19 connectors is over for now.