An Amstrad PCW For The 21st Century

October 30, 2017 by Jenny List 12 Comments

If you were a computer-mad teen in the late 1980s, you were probably in the process of graduating from an 8-bit machine to a 16-bit one, maybe an Amiga, or an Atari ST. For the first time though you might not have been the only computer owner in your house, because there was every chance your parents might have joined the fun with a word processor. Maybe American home offices during this period might have had PC clones, but for Brits there was every chance that the parental powerhouse would have been an Amstrad PCW.

Amstrad were the masters of packaging up slightly outdated technology for electronic consumers on a budget, and the PCW was thus a 1970s CP/M machine for the 1980s whose main attraction was that it came with monitor and printer included in the price. [James Ots]’ parents had one that interested him enough that he has returned to the platform and is documenting his work bringing it up to date.

It was the most recent progress in booting into CP/M from an SD card by hijacking the printer ROM that caught our eye, but reading all the build logs that is only the tip of the iceberg. He’s connected another monitor, made a joystick port and a soundcard, and added a memory upgrade to his PCW. Most of these machines would have only been used with the bundled word processor, so those are real enhancements.

We’ve featured quite a few projects involving Amstrad’s CPC home computers, such as this one with a floppy emulator. Amstrad are an interesting company for followers of consumer electronics of the ’70s and ’80s, they never had the out-there tech wackiness of their great rival Sinclair but their logo could be found on an astonishing variety of appliances. The “AMS” in Amstrad are the initials of the company founder [Alan Sugar], who is rather better known in 2017 as the British host of The Apprentice. It is not known whether he intends to lead the country.

PCB Tesla Coil Is Perfect Desk Toy

October 30, 2017 by Tom Nardi 43 Comments

A Tesla coil easily makes it to the top spot on our list of “Mad Scientist” equipment we want for the lab, second only to maybe a Jacob’s Ladder. Even then, it’s kind of unfair advantage because you know people only want a Jacob’s Ladder for that awesome sound it makes. Sound effects not withstanding, it’s Tesla coil all the way, no question.

Unfortunately, winding your own Tesla coil is kind of a hassle. Even on relatively small builds, you’ll generally need to setup some kind of winding jig just to do the secondary coil, which can be a project in itself. So when [Daniel Eindhoven] sent his no-wind Tesla coil into the tip line, it immediately got our attention.

The genius in his design is that the coils are actually etched into the PCB, completely taking the human effort out of the equation. Made up of 6 mil traces with 6 mil separation, the PCB coil manages to pack a 25 meter long, 160 turn coil into an incredibly compact package. As you might expect, such a tiny Tesla coil isn’t exactly going to be a powerhouse, and in fact [Daniel] has managed to get the entirely thing running on the 500 mA output of your standard USB 2.0 port.

In such a low-power setup, [Daniel] was also able to replace the traditional spark gap pulse generator with a PIC18F14K50 microcontroller, further simplifying the design. An advantage of using a microcontroller for the pulse generator is that it’s very easy to adjust the coil’s operating frequency, allowing for neat tricks like making the coil “sing” by bringing its frequency into the audible range.

For those looking to build their own version, [Daniel] has put the PCB schematic and firmware available for download on his site. He also mentions that, in collaboration with Elektor magazine, he will be producing a kit in the near future. Definitely something we’ll be keeping an eye out for.

Incidentally, this isn’t the first time [Daniel] has demonstrated his mastery of high voltage. He ~~scared~~ impressed us all the way back in 2010 with his 11,344 Joule capacitor bank, perfect for that laptop-destroying rail gun you’ve been meaning to build.

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Analyzing The 6502 With Python And Cheap Dev Boards

October 29, 2017 by Brian Benchoff 10 Comments

The Before Times were full of fancy logic analyzers. Connect the leads on these analyzers to a system, find that super special ROM cartridge, and you could look at the bus of a computer system in real time. We’ve come a long way since then. Now we have fast, cheap bits of hardware that can look at multiple inputs simultaneously, and there are Open Source solutions for displaying and interpreting the ones and zeros on a data bus. [hoglet] has built a very clever 6502 protocol decoder using Sigrok and a cheap 16-channel logic analyzer.

This protocol decoder is capable of looking at the ones and zeros on the data bus of a 6502-based computer. Right now, [hoglet] able to stream two million 6502 cycles directly to memory, so he’s able to capture the entire startup sequence of a BBC Micro. The hardware for this build was at first an Open Bench Logic Sniffer on a Papilio One FPGA board. This hardware was changed to an impressively inexpensive Cypress FX2 development board that was reconfigured to a 16 channel logic analyzer.

The software stack is where this really shines, and here [hoglet] documented most of the build over on the stardot forums. The basic capture is done with Sigrok, the Open Source signal analysis toolchain. This project goes a bit further than simply logging ones and zeros to a file. [hoglet] designed an entire 6502 protocol decoder with Python. Here’s something fantastic: this was [hoglet]’s first major Python project.

To capture the ones and zeros coming out of a 6502, the only connections are the eight pins on the data bus, RnW, Sync, Rdy, and Phy2. That’s only twelve pins, and no connections to the address bus, but the protocol decoder quickly starts to predict what the current program counter should be. This is a really fantastic piece of work, enabling an entire stack trace on any 6502 computer for less than $20 in parts.

Hollow State Memory

October 26, 2017 by Al Williams 12 Comments

A lot of people like tubes either for their audio sound or their collectible value. [Uniservo] likes oddball tubes. His recent video (see below) shows a radechon — a computer memory tube. These were apparently widely used in RADAR sets until recently and has some similarity to a Williams tube.

The tube is essentially a CRT that illuminates a sheet of mica or another dielectric instead of a phosphor screen. The dielectric has a fine mesh grid in contact with it. By depositing charge on the mica, the tube can store an analog value. In theory, the tube could store about 16 kbits of information, but in practice, the resolution was less.

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Reconstructing A Blurry QR Code

October 26, 2017 by Lewin Day 4 Comments

QR Codes are a two-dimensional type of matrix barcode that are used for a variety of uses. They’re one way of turning a long piece of string data into an easily machine-readable format. For this reason, they can be used to store private keys for encryption and crypto-currency purposes. [Roger Ver] attempted to use a QR code containing a private key to give away some cryptocurrency on TV, but the code was blurred out by the broadcaster. Not ones to give up easily, [Michael] and [Clément] decided to see if they could reconstruct it anyway.

The work begins, as so many cryptographic exploits do, with the collection of as much of the plaintext key as possible. By stepping through the footage frame by frame, small pieces of the unobscured QR code were found, as well as some of the private key itself. By combining this with enhanced images of the blurred code, the team were able to put together less than one third of the QR code. The team had other tricks up their sleeve though – they knew the QR contained a private key of a particular format, and were able to figure out the QR code was 41×41 pixels.

By using this data along with a careful study of the QR code format, the team were able to put together some code in Python to brute force the key. After 838849 trials, the key was found, and the team were able to claim the prize. It’s a great example of cryptographic analysis – and so is this story on hacking your own password.

[Thanks to Esko for the tip!]

Restoring A Tonka Truck With Science

October 26, 2017 by Tom Nardi 36 Comments

The yellow Tonka Truck. Instantly recognizable by any child of decades past, that big metal beast would always make you popular around the sandbox. There were no blinking lights to dazzle, no noises to be heard (unless you count the hard plastic wheels rolling on concrete), even the dumping action is completely manual. But back then, it was a possession to be treasured indeed.

So it’s perhaps no surprise that there is a certain following for these classic trucks today, though like with most other collectibles, a specimen in good condition can be prohibitively expensive. The truck that [PoppaFixIt] found in the trash was certainly not one of those specimens, but with some patience and knowledge of basic chemistry, he was able to bring this vintage toy back to the present.

The first step was to disassemble the truck. Before they switched over to Chinese mass production, these trucks were built with actual rivets. After drilling them out and unfolding the little metal tabs that toy makers loved back in the day, he was able to separate the metal body of the truck from the plastic detail bits. The plastic parts just needed a fresh coat of paint, but the rusted metal body would need a bit more attention.

Remembering a tip he read online, [PoppaFixIt] decided to attempt electrolytic rust removal to get the metal parts back into serviceable condition. A big plastic bin, some washing soda, and old steel window weights for his sacrificial anodes was all the equipment he needed for the electrolysis tank. To power the chemical reaction he used a standard 12 volt car battery and charger wired in parallel; this step is important, as he notes most newer chargers are smart enough not to work unless they see a real battery connected.

After running the setup overnight, the collected rust and junk on the window weights was proof enough the process worked. From there, it was just a fresh coat of yellow paint, a new sticker kit from eBay, and his Tonka truck was ready to face another 30+ years of service.

If you’re looking to restore things larger than a child’s toy, you may be interested in the much larger electrolytic setup we’ve covered previously. Of course if you’re really pressed for time, you could try blasting the rust away with a laser.

Imperial Rocker For Stopping Tiny Rebel Scum

October 25, 2017 by Tom Nardi 15 Comments

Some of the luckiest kids in the world have to be the ones with hackers and makers as parents. While normal kids are stuck playing with cookie cutter mass produced toys, these kids get one-off gadgets and creations that will be the envy of the playground. Frankly, some of the stuff ends up being so cool that it’ll get the adults wishing they could go back in time and play with it.

One such parent, and one such project, is the Imperial Rocker by [Matthew Regonini]. Hoping to instill an obsession with a galaxy far, far, away on his offspring, [Matthew] designed this AT-AT rocking horse piece by piece in Illustrator, and then cut it all out of birch using his XCarve CNC router. Each piece was then meticulously glued together to produce a final 3D effect from the individual cutouts.

With a liberal application of spring clamps to hold it all together while it dried, all that was left to do was painstakingly sand all the parts so the edges of the laminated construction would be smooth. Dowels were then added for the handlebars and foot pegs, and a few coats of polyurethane seal up the plywood while bringing out a natural look.

[Matthew] notes some issues here and there, notably quite a bit of blowout in some of the detail cuts and a couple miscalculated dimensions. But he reasons that the rocker is going to live a pretty hard life anyway, so best not to sweat the small stuff.

While the Imperial Rocker has that quaint old-school charm, we wonder how long it will be before [Matthew’s] little Stormtrooper starts yearning for the blinking lights and buttons that youngsters just can’t get enough of.

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