Building RAM Expansions For The DEC Rainbow 100

It’s hard enough to get your hands on a forgotten computer from yesteryear. It’s even more difficult to get accessories like RAM expansions and graphics cards, because half the time they’re just discarded as random e-waste when they’re outside of their original context. [na103] has solved this problem for the DEC Rainbow 100 to a degree, by building new RAM expansions and graphics cards from scratch.

In the case of the RAM expansion, the design [na103] built is capable of boosting a Rainbow 100 computer to a full 896KB. This is more than other contemporary IBM machines like the 8088 XT, which had an architecture-enforced limit of 640 KB.  It was rebuilt from some notes and original DEC schematics.

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A colorful diagram representing the inner structure of the Linux kernel.

Find That Obscure Function With This Interactive Map Of The Linux Kernel

Linux has become one of the largest operating systems on the servers that run large websites, and hopefully, one day, it will be big in the desktop market too. Some of you may know how Linux as an operating system is structured, but have you ever wondered how the kernel itself is structured? Maybe you’ll find this colorful interactive map of the Linux kernel by [Costa Shulyupin] useful.

The interactive map depicts the major levels of abstraction and functionalities, dotted with over 400 prominent functions from the Linux kernel, which are also links to a cross-reference site so you can see all the definitions and usages. It divides the kernel into 7 rows and 7 columns containing domains with well-known terms like security and debugging, but also more obscure things like block devices and address families. These are also links, this time to the definition of the term in question. Finally, there are arrows flying everywhere, to show the relationships between all the many functions in the kernel.
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Bare Bones Vacuum Forming, Just Add Plastic Plates

Vacuum forming is a handy thing to be able to do, and [3DSage] demonstrates how to do a bare-bones system that can form anything smaller than a dinner plate with little more than a 3D printed fitting to a vacuum cleaner, a heat gun, and a trip to the dollar store.

Plastic plates from the dollar store make excellent forming sheets, and in a variety of colors.

The 3D printed piece is a perforated table that connects to a vacuum cleaner hose, and [3DSage] mentions elsewhere that he tried a few different designs and this one worked the best. A cardboard box makes an expedient stand. The object being molded goes on the table, and when the vacuum is turned on, air gets sucked down into the holes.

As for the thermoforming itself, all that takes is some cheap plastic plates and a heat gun. Heat the plastic until it begins to droop, then slap it down onto the vacuum table and watch the magic happen. Using plastic plates like this is brilliant. Not only are they economical, but their rim serves as a built-in handle and helps support the sagging plastic.

Thermoforming plastic on a 3D-printed vacuum table and using 3D-printed molds definitely isn’t a system that will be cranking parts out all day long, but as long as one allows time for everything to cool off in between activations, it’ll get the job done. Nylon will hold up best but even PLA can be serviceable.

Watch it in action in the video embedded below. The video is actually about [3DSage] making adorable Game Boy themed s’mores, but here’s a link to the exact moment the vacuum forming part happens.

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Building A Rotating Display Plate From A Lazy Susan

A rotating table is a super nifty tool for all kinds of photography and videography purposes. [Handy Bear] built a super simple example using some parts from IKEA.

The build starts with a Snudda, which is IKEA’s version of a Lazy Susan. It’s fitted with a 3D-printed gear to allow it to be easily driven. The platter is then fitted to a 3D printed base, which also contains the drive electronics, and driven by a small brushed DC gear motor. An off-the-shelf speed controller was employed to allow the speed of the platter to be varied as required.

[Handy Bear] does a good job of explaining how to build the project properly while avoiding the usual pitfalls. In particular, he demonstrates how to fit the gear to the platter without getting it off-axis. We also appreciate a design that can be built virtually anywhere thanks to using commonly-available parts.

We’ve featured other rotating tables before, like this open-ended design that was built on a much larger scale. Video after the break.

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Machine Learning Robot Runs Arduino Uno

When we think about machine learning, our minds often jump to datacenters full of sweating, overheating GPUs. However, lighter-weight hardware can also be used to these ends, as demonstrated by [Nikodem Bartnik] and his latest robot.

The robot is charged with autonomously navigating a simple racetrack delineated by cardboard barriers. The robot is based on a two-wheeled design with tank-style steering. Controlled by an Arduino Uno, the robot uses a Slamtec RPLIDAR sensor to help map out its surroundings. The microcontroller is also armed with a Bluetooth link and an SD card for storage.

The robot was first driven around the racetrack multiple times under manual control, all the while collecting LIDAR data. This data was combined with control inputs to help create a data set that could be used to train a machine learning model. Feature selection techniques were used to refine down the data points collected to those most relevant to completing the driving task. [Nikodem] explains how the model was created and then refined to drive the robot by itself in a variety of race track designs.

It’s a great primer on machine learning techniques applied to a small embedded platform.

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Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Death Metal Macro Pad

At “the size of three 60% keyboards (put together)” or approximately one Cannibal Corpse record on vinyl, this beautifully-executed death metal font-inspired macro pad by [zyumbik] may be better off hanging on the wall than hanging out on the desktop.

But let’s say you did have room for the 9-key Deathpad on your desktop. Wouldn’t you just play with the tentacles (?) all the time like I would? Yeah, that’s what I thought. They’re pretty inviting.

So why does this look so fantastic? It’s an SLA print, for one thing. For another, [zyumbik] spent over 1,000 hours designing the thing. Unfortunately it’s not open-source, but you can buy the only other one in existence for a cool $1,000.

Rubik’s Cube Keyboard

Although it doesn’t rotate (yet), creator [_Rudeism] is calling this the Rubik’s Cube Keyboard. Fine with me, though any type of actual rotation would be insanely difficult to pull off. The plan is to do it with RGB LEDs.

The layout is QWERTY-adjacent — the white side is the num pad, yellow has the modifiers, and the other four sides house all the letters. As you might imagine, this uses a custom frame and PCBs. The switches are Glorious Gateron Clears, which definitely supports the blinkenlights planned for V2.

This thing reminds me a bit of of the SafeType™ vertical keyboard, or even [Aaron Rasmussen]’s spherical keyboard. Be sure to check it out in Monkeytype action, where [_Rudeism] manages to pull off about 20WPM. Continue reading “Keebin’ With Kristina: The One With The Death Metal Macro Pad”

A black race car with white text of sponsors moves across an asphalt surface. There is a blue wall and a green, grassy field in the background. The car has white and red stripes as well.

Students Set EV Acceleration World Record

Humans have a need for speed, and students from the Academic Motorsports Club Zurich (AMZ) have set a new acceleration record for an electric vehicle with a 0 to 100 km/h (0 to 62 mph) time of 0.956 seconds.

The mythen features four custom electric hub motors with a total output of 240 kW and a vehicle weight of 140 kg (309 lb) thanks to the use of carbon fiber and aluminum honeycomb. The car was able to get up to speed over only 12.3 m (40 ft)! As with many student design team projects, every component was hand built and designed to optimize the power to weight ratio of the vehicle.

The students from ETH Zurich and Lucerne University of Applied Sciences and Arts were excited to regain the record from the team at the University of Stuttgart, having previously held the title in 2014 and 2016. We suspect that they will find any European EV maker’s engineering department excited for the chance to hire them come graduation.

If you want to go fast at a smaller scale, checkout 3D printing RC car wheels for speed, and if you’d rather ride the rails at an accelerated rate, here’s an article on high speed rail.

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