classic hacks

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Raspberry Pi Becomes Cycle Exact Commodore Drive Emulator

May 7, 2018 by 83 Comments

The Commodore 1541 disk drive is unlike anything you’ll ever see in modern computer hardware. At launch, the 1541 cost almost as much as the Commodore 64 it was attached to ($400, or about $1040 at today’s value). This drive had a CPU, and had its own built-in operating system. Of course, anyone using a Commodore 64 now doesn’t deal with this drive these days — you can buy an SD2IEC for twenty dollars and load all your C64 games off an SD card. If you’re cheap, there’s always the tape drive interface and a ten dollar Apple Lightning to 3.5mm headphone adapter.

But the SD2IEC isn’t compatible with everything, and hacking something together using the tape drive doesn’t have the panache required of serious Commodoring. What’s really needed is a cycle-accurate emulation of the 1541 disk drive, emulating the 6502 CPU and the two 6522 VIAs in this ancient disk drive. The Raspberry Pi comes to the rescue. [Steve White] created the Pi1541, an emulation of the Commodore 1541 disk drive that runs on the Raspberry Pi 3B.

Pi1541 is a complete emulation of the 6502 and two 6522s found inside the Commodore 1541 disk drive. It runs the same code the disk drive does, and supports all the fast loaders, demos, and copy protected original disk images that can be used with an original drive.

The only hardware required to turn a Raspberry Pi 3 into a 1541 are a few transistors in the form of a bi-directional logic level shifter, and a plug for a six-pin serial port cable. This can easily be constructed out of some Sparkfun, Adafruit, Amazon, or AliExpress parts, although we suspect anyone could whip up a Raspberry Pi hat with the same circuit in under an hour. The binaries necessary to run Pi1541 on the Raspberry Pi are available on [Steve]’s website, and he’ll be releasing the source soon.

This is a great project for the retrocomputing scene, although there is one slight drawback. Pi1541 requires a Raspberry Pi 3, and doesn’t work on the Raspberry Pi Zero. That would be an amazing bit of software, as ten dollars in parts could serve as a complete emulation of a Commodore disk drive. That said, you’re still likely to be under $50 in parts and you’re not going to find a better drive emulator around.

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Commodore 64 To Raspberry Pi Conversion Is Respectful & Complete

May 4, 2018 by 27 Comments

We’re big fans of taking old computers and giving them a new lease on life, but only when it is done respectfully. That means no cutting, no hot glue, and no gouging out bits to make the new computer fit. It’s best if it can be done in a way that the original parts can be restored if required.

This Commodore 64 to Raspberry Pi conversion from [Mattsoft] definitely fits our criteria here, as it uses the old keyboard, joystick connectors and output portholes for the required authentic look. It does this through the clever use of a couple of 3D-printed parts that hold the Raspberry Pi and outputs in place, mounting them to use the original screw holes in the case.

Combine the Pi with a Keyrah V2 to connect the C64 keyboard and a PowerBlock to juice up all of the parts, and you’ve got a fully updated C64 that can use the keyboard, joysticks or other peripherals, but which also comes with a HDMI port, USB and other more modern goodies.

[Mattsoft] suggests using Combian 64, a C64 emulator for the Pi for the authentic look and feel. Personally, I might use it as a thin client to the big-ass PC with 16 CPU cores and 32GB of memory that’s hidden in my basement, but that’s just because I enjoy confusing people.

Oddball Mercury Vapor Rectifier Is A Tube Geek’s Delight

May 2, 2018 by 29 Comments

Even if you aren’t a tube aficionado, you can’t help but be mesmerized by the blue glow inside a mercury vapor rectifier when it operates. It looks less like early 20th century tech and more like something that belongs on a Star Trek set. [Uniservo] acquired an 866 rectifier that was interesting due to the markings, which he explains in detail in the video below. Most people though will probably want to skip to closer to its end to see that distinctive blue glow. The exact hue depends on the mercury vapor pressure and usually contains a fair amount of ultraviolet light.

These tubes have an interesting history dating back to 1901, the year [Peter Cooper Hewitt] developed a mercury vapor light which was much more efficient than conventional bulbs. They had two main problems, they required some special process to get the mercury inside to vaporize when you turned them on, but worse still, the light was blue-green which isn’t really appropriate for home and office lighting. In 1902 though, [Hewitt] realized the tube would act as a rectifier. Electrons could readily flow out of the mercury vapor that was the cathode, while the carbon anodes didn’t give up electrons as readily. This was important because up until then, there wasn’t an easy way to convert AC to DC. The usual method was to use an AC motor coupled to a DC generator or a similar mechanical arrangement known as a rotary converter.

In later decades the mercury vapor lamp would wind up with a phosphor coating that converted the ultraviolet light to cool white light and became the fluorescent bulb, so while the rectifier mostly gave way to more efficient methods, [Hewitt’s] bulb has been in use for many years.

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The Internet Of Claw Machines

May 2, 2018 by 8 Comments

Remote administration of machines is a very useful tool for all manner of commercial, industrial, and home applications. Now, it’s available for claw machines, too – thanks to [Code Your Venture Free].

The project uses an ESP32 board that includes a battery case on the back for a standard 18650 lithium battery that makes getting small battery powered projects off the ground much easier. You can find them at Banggood and AliExpress, but we’re not 100% sure that they’re kosher because they’re branded WeMos, but don’t show up on WeMos’ website or their official online retail store. Anyway, it’s a cute idea to strap a LiPo cell to the back like that. Let us know in the comments if you know more.

Back to the claw! An off-the-shelf thumbstick is then connected to the ESP32 which is programmed to send packets over the network to control the claw machine, which is wired up with its own network-connected microcontroller. It’s all wrapped up in the usual 3D printed case.

The one problem that the project doesn’t solve is delivery – how does the remote player, whether on the local network or online, collect their prize? We can only assume some cutting-edge form of drone delivery is the solution. It’s not the first remote claw machine we’ve seen, either. Video after the break.

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See-Through Rotary Engine Reveals Wankel Magic

May 1, 2018 by 25 Comments

The Wankel rotary engine is known for its troubled life in the mainstream automotive industry, its high power-to-weight ratio, and the intoxicating buzz it makes at full tilt. Popular with die-hard enthusiasts and punishing to casual owners, it stands as perhaps the most popular alternative internal combustion design to see the light of day. There are myriad diagrams out there to explain its operation, but what if you could see inside?

The video comes courtesy of [Warped Perception], and features a small Wankel rotary engine intended for model aircraft. The engine’s end plate is removed and replaced with a transparent plate, making the combustion process visible. Add in a high-speed camera, and you’ve got a recipe for a great technical video.

It starts with a basic explanation of how the Wankel rotary power cycle operates, before cutting to the glorious slow-motion shots of the engine in operation. It also highlights several techniques useful for producing this type of video, such as painting surrounding components black to make it easier to image the parts of interest. The visuals are amazing and very clearly show the  manner in which the intake, compression, power and exhaust strokes function in the engine.

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Recycling And Casting Styrofoam With Solvents

May 1, 2018 by 31 Comments

Styrofoam is an ever-present waste material in modern society, being used to package everything from food to futons. It’s also not the easiest thing to deal with as a waste stream, either. With this in mind, [killbox] decided to have a go at recycling some styrofoam and putting it to better use.

The process starts by combining the EPS styrofoam with a solvent called D-limonene. This was specifically chosen due to its low toxicity and ease of use. The solvent liquifies the solid foam and the air bubbles are then allowed to make their way out of the solution. If it’s desired to create a coloured end product, it’s noted that this can be achieved by using other plastic items to provide colour at this stage, such as a red Solo cup.

It’s a slow process thanks to the choice of solvent, but it makes the process much more palatable to carry out in the average home lab setup. It’s possible to then perform casting operations or further work with the recovered material, which could have some interesting applications. It’s not the first plastics recycling project we’ve seen, either – check out this full setup.

[Thanks to Adric for the tip!]

The Interesting Fate Of Kenya’s First Computers

April 28, 2018 by 20 Comments

If you are an enthusiast for 1950s computer hardware, you are probably out of luck when it comes to owning a machine of your own. Your best chance will be to join the staff of one of the various museums that preserve and operate these machines, at which you can indulge your passion to your heart’s content. But what if we told you that there is a 1950s computer available for pick-up at any time, to whoever is prepared to go and get it and has suitable transport? You’d be making plans straight away, wouldn’t you? The computer in question is real, but there’s a snag. It’s at the bottom of the Indian Ocean, just at the start of international waters off the coast of Kenya. The story of Kenya’s early computing and how the machine met its fate is the subject of a fascinating article from a year or two ago on owaahh.com that had us riveted from start to finish.

Like large state-owned enterprises worldwide, the Kenyan railway and power monopolies were among the first commercial customers for computing. In the final years of the British Empire, those were ordered from a company in London, International Computers & Tabulators, and it was their ICT1202 that served the railway company. The article goes into detail about the history of the company’s East African operation, the problems of running a tube-based computer in an African climate without air-conditioners, and the 1202’s demise and replacement. We’ll not spill the beans here on how the computer ended up on the seabed and how its replacement ended up being spirited away to China, for that you’ll have to read it all. It’s worth saying, the author also has a personal website in which he goes into much more detail about his experience with computers in the 1950s and ’60s.

Not had enough ancient computer tech? A couple of years ago we toured the primordial electronic computer, Colossus, and also took a look at the National Museum Of Computing that houses it.