A New Mechanical Keyboard For An Old Computer

April 10, 2025 by Bryan Cockfield 9 Comments

As computers age, a dedicated few work towards keeping some of the more interesting ones running. This is often a losing battle of sorts, as the relentless march of time comes for us all, human and machine alike. So as fewer and fewer of these machines remain new methods are needed to keep them running as best they can. [CallousCoder] demonstrates a way of building up a new keyboard for a Commodore 64 which both preserves the original look and feel of the retro computer but also adds some modern touches.

One of the main design differences between many computers of the 80s and modern computers is that the keyboard was often built in to the case of the computer itself. For this project, that means a custom 3D printed plate that can attach to the points where the original keyboard would have been mounted inside the case of the Commodore. [CallousCoder] is using a print from [Wolfgang] to get this done, and with the plate printed and a PCB for the keys it was time to start soldering. The keyboard uses modern switches and assembles like most modern keyboards do, with the exception of the unique layout for some of the C64 keys including a latching shift key, is fairly recognizable for anyone who has put together a mechanical keyboard before.

[CallousCoder] is using the original keycaps from a Commodore 64, so there is an additional step of adding a small adapter between the new switches and the old keycaps. But with that done and some amount of configuring, he has a modern keyboard that looks like the original. If you’re more a fan of the original hardware, though, you can always take an original C64 keyboard and convert it to USB to use it on your modern machines instead.

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3D Print (and Play!) The Super Mario Tune As A Fidget Toy

April 4, 2025 by Donald Papp 34 Comments

[kida] has a highly innovative set of 3D-printable, musical fidget toys that play classic video game tunes. Of course there’s the classic Super Mario ditty, but there’s loads more. How they work is pretty nifty, and makes great use of a 3D printer’s strengths.

To play the device one uses a finger to drag a tab (or striker) across the top, and as it does so it twangs vertical tines one-by-one. Each tine emits a particular note — defined by how tall the thicker part is — and plays a short tune as a result. Each one plays a preprogrammed melody, with the tempo and timing up to the user. Listen to them in action in the videos embedded just under the page break!

There are some really clever bits to the design. One is that the gadget is made in two halves, which effectively doubles the notes one can fit into the space. Another is that it’s designed so that holding it against something like a tabletop makes it louder because the surface acts like a sounding board. Finally, the design is easily modified so making new tunes is easy. [kida]’s original design has loads of non-videogame tunes (like the Jeopardy! waiting theme) as well as full instructions on making your very own versions.

Fidget toys are a niche all their own when it comes to 3D printed devices. The fidget knife has a satisfying snap action to it, and this printable linear toggle design is practically a fidget toy all on its own.

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Solar-Powered E-Reader With No Buttons

March 10, 2025 by Bryan Cockfield 21 Comments

Modern e-readers such as the Amazon Kindle are incredible pieces of engineering, but that doesn’t mean there’s no room for improvement. A device custom-built to your own specifications is always going to provide a more satisfying experience than something purchased off the shelf. That’s why [fel88] put together this custom e-reader which offers a number of unique features, such as a solar panel on the back and button-free operation.

One issue with modern e-readers, at least as [fel88] sees it, is that they have a lot of unnecessary features. This project removes most of them, stripping down the device to its core functionality: a straightforward menu for selecting books and gesture-sensing for navigating the menu as well as changing the pages. The only physical input on the device is a small reed switch to turn the device on. A 3D printed case holds the e-ink display and encloses the inner workings, driven by an Arduino Mega 2560 and powered by three lithium-ion capacitors (LICs) and a small solar panel.

By dropping all of the unnecessary features, the device doesn’t need to waste energy with things like WiFi or Bluetooth and can get around 880 pages on a single charge, not counting any extra energy coming in through the solar panel while it’s operating. The LICs will also theoretically improve its life cycle as well. If you’re still stuck with a paperweight when you formerly had a working e-reader, though, there are plenty of ways to bring old devices back to life as well.

DIY Open-Source Star Tracker Gets You Those Great Night Shots

February 25, 2025 by Donald Papp 15 Comments

What does one do when frustrated at the lack of affordable, open source portable trackers? If you’re [OG-star-tech], you design your own and give it modular features that rival commercial offerings while you’re at it.

What’s a star tracker? It’s a method of determining position based on visible stars, but when it comes to astrophotography the term refers to a sort of hardware-assisted camera holder that helps one capture stable long-exposure images. This is done by moving the camera in such a way as to cancel out the effects of the Earth’s rotation. The result is long-exposure photographs without the stars smearing themselves across the image.

Interested? Learn more about the design by casting an eye over the bill of materials at the GitHub repository, browsing the 3D-printable parts, and maybe check out the assembly guide. If you like what you see, [OG-star-tech] says you should be able to build your own very affordably if you don’t mind 3D printing parts in ASA or ABS. Prefer to buy a kit or an assembled unit? [OG-star-tech] offers them for sale.

Frustration with commercial offerings (or lack thereof) is a powerful motive to design something or contribute to an existing project, and if it leads to more people enjoying taking photos of the night sky and all the wonderful things in it, so much the better.

Infill Injection Experiment Makes Stronger Parts

February 25, 2025 by Donald Papp 28 Comments

[JanTec Engineering] was fascinated by the idea of using a 3D printer’s hot end to inject voids and channels in the infill with molten plastic, leading to stronger prints without the need to insert hardware or anything else. Inspiration came from two similar ideas: z-pinning which creates hollow vertical channels that act as reinforcements when filled with molten plastic by the hot end, and VoxelFill (patented by AIM3D) which does the same, but with cavities that are not uniform for better strength in different directions. Craving details? You can read the paper on z-pinning, and watch VoxelFill in (simulated) action or browse the VoxelFill patent.

With a prominent disclaimer that his independent experiments are not a copy of VoxelFill nor are they performing or implying patent infringement, [JanTec] goes on to use a lot of custom G-code (and suffers many messy failures) to perform some experiments and share what he learned.

Using an airbrush nozzle as a nozzle extension gains about 4 mm of extra reach.

One big finding is that one can’t simply have an empty cylinder inside the print and expect to fill it all up in one go. Molten plastic begins to cool immediately after leaving a 3D printer’s nozzle, and won’t make it very far down a deep hole before it cools and hardens. One needs to fill a cavity periodically rather than all in one go. And it’s better to fill it from the bottom-up rather than from the top-down.

He got better performance by modifying his 3D printer’s hot end with an airbrush nozzle, which gave about 4 mm of extra length to work with. This extra long nozzle could reach down further into cavities, and fill them from the bottom-up for better results. Performing the infill injection at higher temperatures helped fill the cavities more fully, as well.

Another thing learned is that dumping a lot of molten plastic into a 3D print risks deforming the print because the injected infill brings a lot of heat with it. This can be mitigated by printing the object with more perimeters and a denser infill so that there’s more mass to deal with the added heat, but it’s still a bit of a trouble point.

[JanTec] put his testing hardware to use and found that parts with infill injection were noticeably more impact resistant than without. But when it came to stiffness, an infill injected part resisted bending only a little better than a part without, probably because the test part is very short and the filled cavities can’t really shine in that configuration.

These are just preliminary results, but got him thinking there are maybe there are possibilities with injecting materials other than the one being used to print the object itself. Would a part resist bending more if it were infill injected with carbon-fibre filament? We hope he does some follow-up experiments; we’d love to see the results.

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MIT Demonstrates Fully 3D Printed, Active Electronic Components

February 19, 2025 by Donald Papp 27 Comments

One can 3D print with conductive filament, and therefore plausibly create passive components like resistors. But what about active components, which typically require semiconductors? Researchers at MIT demonstrate working concepts for a resettable fuse and logic gates, completely 3D printed and semiconductor-free.

Now just to be absolutely clear — these are still just proofs of concept. To say they are big and perform poorly compared to their semiconductor equivalents would be an understatement. But they do work, and they are 100% 3D printed active electronic components, using commercially-available filament.

How does one make a working resettable fuse and transistor out of such stuff? By harnessing thermal expansion, essentially.

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Tiny RC Four-Wheeler Gets Chassis Upgrade For More Traction

February 2, 2025 by Lewin Day 9 Comments

[Azpaca] purchased a fun little toy car from Tamiya, only… there was a problem. The little off-roader wasn’t up to scratch—despite its four-wheel-drive, it couldn’t get over rough ground to save its life. Thus, it was time to 3D-print a better chassis that could actually get through it!

The problem was quite obvious. With no suspension and a rigid chassis, the vehicle would tend to end up with one or more wheels on the air on rough surfaces. To rectify this, [Azpaca] created a twisting chassis which would allow the wheels to better remain in contact with the ground. The design is relatively straightforward, and reuses much of the original drivetrain, including the simple brushed motor. However, with a pivot right behind the front wheels, it has much more traction on rocks and gravel, and can traverse these terrains much more easily.

Tamiya’s motorized toys aren’t particularly well known in the West, but it’s neat to see the community that exists around modifying them around the world. Design files are available for the curious. If you’re not down with mods, perhaps you’d prefer to print your own cars from scratch. Video after the break.

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