Ancient Instrument Goes Digital: The Digi-Gurdy

The hurdy-gurdy is a fascinating string instrument dating from sometime around the 10th century. There is an active community of modern enthusiasts, but one can’t simply walk into a music shop and buy one. That’s where [XenonJohn] and the Digi-Gurdy come in, bringing some nice features while maintaining all the important elements of the original.

The mechanical keys and crank of the Hurdy-Gurdy are preserved in this modern digital incarnation.

The hurdy-gurdy works by droning strings with a rotating wheel, and the player applies pressure to those strings via keys to play combinations of notes. Here’s a video demonstrating what it sounds like to play one, and one can see a conceptual resemblance to bagpipes, among other things.

The Digi-Gurdy is a modern electronic version that maintains the mechanical elements while sending MIDI signals over USB. It has options for line-out or headphone output. A thriving online community has shaped its development since its inception years ago.

We hope this leaves you wanting to know more because [XenonJohn] has loads of details to share. The main website at digigurdy.com is jam-packed with information about this instrument and its construction, and the project page on Hackaday.io has more nitty-gritty design details and source files for those who crave hardware specifics.

If [XenonJohn]’s name sounds familiar, it’s because we’ve admired his work on DIY self-balancing vehicles over the years. He also submitted an earlier version as an entry into the Hackaday Prize. His careful attention to detail shines through. Check out the two videos (embedded just below the page break): the first demonstrates the Digi-Gurdy, and the second shows off the construction and insides. You’d think a MIDI hurdy-gurdy would be unique, but, actually, we’ve seen more than one.

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TOPS, The DIY Robot Dog, Has Great Moves

We love [Aaed Musa]’s TOPS (Traverser of Planar Surfaces) which is a robot dog with custom-made actuators. The DIY is very strong with this project, and the 3D-printed parts alone took a whopping three weeks to print!

There’s additional detail on the electronics and design of TOPS in the build log of the project’s Hackaday.io page, so check it out because there are all sorts of nice design details, like the feet being cast with a silicone outer layer for better traction. We’ve previously covered [Aaed]’s DIY robotic actuator design which we’re delighted to see is put to excellent use in the finished robot.

Of course, a robot’s hardware and physical design is only part of the battle. In fact, [Aaed] says the software side of things was probably the biggest overall challenge. It takes a lot of work to make walking happen, and the process has in fact been a huge learning experience. [Aaed] already has plenty of ideas for a potential TOPS V2.

[Aaed]’s website has video tours of all stages of design and construction of TOPS, and there’s a GitHub repository for all the design details. To see it all in action, check out the short video rounding up the finished robot, embedded here just under the page break.

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Micro Jeep Model Kit Is Both Business Card And Portfolio

When finding work in product design and prototyping, two things are important to have at hand: a business card, and a sample of one’s work. If one can combine those, even better. Make it unique and eye-catching, and you’re really onto something. That seems to  have been the idea behind [agepbiz]’s 1:64 scale micro Jeep model kit that serves as an  “overcomplicated” business card.

Complete with box and labels in a shrink-wrapped package.

At its heart, the kit is a little print-in-place model kit that looks a lot like larger injection-molded model kits. Completing it is a custom-made box with custom labels, and it’s even shrink-wrapped. The whole thing fits easily in the palm of a hand.

There’s a lot of different tools effectively used to make the whole thing. The model card itself is 3D printed in multiple filament colors, and the box is constructed from carefully glued cardstock. The labels are custom printed, and a craft cutter (which has multiple uses for a hobbyist) takes care of all the precise cutting. It’s an awfully slick presentation, and the contents do not disappoint.

Get a closer look in the video, embedded just below. And if you like what you see, you’re in luck because we’ve seen [agepbiz]’s work before in this mini jet fighter, complete with blister pack.

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Design Tips To Hide Layer Lines In 3D Printed Parts

[Slant 3D] knows a lot about optimizing 3D prints so that they can be cranked out reliably with minimal need for post-processing, and in this short video he uses a cube as a simple example of how a few design changes can not only optimize for production, but can even hide layer lines pretty effectively.

Just to be perfectly clear, layer lines cannot be eliminated entirely without some kind of post-processing. But [Slant 3D]’s tips sure goes a long way toward making a part lose that obvious 3D-printed “look”. They also dovetail nicely with advice on how to optimize cranking out high numbers of parts in a print farm.

Adding texture to the outer layer is especially effective when combined with non-traditional part orientations.

One simple way to avoid visible layer lines is to put some kind of texture onto the part. This can be modeled into the part’s surface, or the slicer software can be used to modify the exterior of the print to add a texture such as a geometric pattern or by applying a fuzzy skin modifier.

Printing a texture onto the exterior is great, but the outcome can be even further improved by also printing the object in a non-traditional orientation.

Using a cube as an example, printing the cube on a corner has the advantage of putting the layer lines in a different orientation as well as minimizing the contact area on the print bed. This applies the texture across more of the part, and looks less obviously 3D printed in the process. Minimizing bed adhesion also makes parts much easier to remove, which has obvious benefits for production. [Slant 3D] points out that performing these operations on a 3D-printed part is essentially free.

A few other optimizations for production involve rounding sharp corners to optimize tool travel paths, and putting a slight chamfer on the bottom of parts to avoid any elephant foot distortion (Elephant’s foot can be compensated for, but simply putting a slight chamfer on a part is a design change that helps avoid accounting for machine-to-machine variance.)

Even if one has no need to optimize for high production volume, the tips on hiding layer lines with design changes is great advice. Watch it all in action in the short video, embedded below.

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The Latest Advancements In Portable N64 Modding

[Chris Downing] has been in the mod scene a long time, and his 5th GeN64 Portable is his most modern portable Nintendo 64 yet. The new build has an improved form factor, makes smart use of 3D printing and CNC cutting, efficiently uses PCBs to reduce wiring, and incorporates a battery level indicator. That last feature is a real quality of life improvement, nicely complementing the ability to charge over USB-C.

What’s interesting about builds like this is that it’s all about the execution. The basic parts required to mod a classic games console into a portable unit are pretty well understood, and off-the-shelf modules like button assemblies exist to make the job far easier than it was back in the day when all had to be done from scratch. We’ve admired [Chris Downing]’s previous builds, and what differentiates one mod from another really comes down to layout and execution, and that’s where the 5th GeN64 Portable shines. Continue reading “The Latest Advancements In Portable N64 Modding”

Watch The OpenScan DIY 3D Scanner In Action

[TeachingTech] has a video covering the OpenScan Mini that does a great job of showing the workflow, hardware, and processing method for turning small objects into high-quality 3D models. If you’re at all interested but unsure where or how to start, the video makes an excellent guide.

We’ve covered the OpenScan project in the past, and the project has progressed quite a bit since then. [TeachingTech] demonstrates scanning a number of small and intricate objects, including a key, to create 3D models with excellent dimensional accuracy.

[Thomas Megel]’s OpenScan project is a DIY project that, at its heart, is an automated camera rig that takes a series of highly-controlled photographs. Those photographs are then used in a process called photogrammetry to generate a 3D model from the source images. Since the quality of the source images is absolutely critical to getting good results, the OpenScan hardware platform plays a pivotal role.

Once one has good quality images, the photogrammetry process itself can be done in any number of ways. One can feed images from OpenScan into a program like Meshroom, or one may choose to use the optional cloud service that OpenScan offers (originally created as an internal tool, it is made available as a convenient processing option.)

It’s really nice to have a video showing how the whole workflow works, and highlighting the quality of the results as well as contrasting them with other 3D scanning methods. We’ve previously talked about 3D scanning and what it does (and doesn’t) do well, and the results from the OpenScan Mini are fantastic. It might be limited to small objects, but it does a wonderful job on them. See it all for yourself in the video below.

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Canned Air Is Unexpectedly Supersonic

How fast is the gas coming out from those little duster tubes of canned air? Perhaps faster than one might think! It’s supersonic (video, embedded below) as [Cylo’s Garage] shows by imaging clear shock diamonds in the flow from those thin little tubes.

Shock diamonds are a clear indicator of supersonic flow.

Shock diamonds, normally seen in things like afterburning jet turbine or rocket engine exhaust streams, are the product of standing wave patterns that indicate supersonic speeds. These are more easily visible in jet plumes, but [Cylo’s Garage] managed to get some great images of the same phenomenon in more everyday things such as the flow of duster gas.

Imaging this is made possible thanks to what looks like a simple but effective Schlieren imaging setup, which is a method of visualizing normally imperceptible changes in a fluid’s refractive index. Since the refractive index of a gas can change in response to density, pressure, or temperature, it’s a perfect way to see what’s going on when there’s otherwise nothing for one’s eyeballs to latch onto.

Intrigued by this kind of imaging? It requires a careful setup, but nothing particularly complicated or hard to get a hold of. Here’s one such setup, here’s a Schlieren videography project, and here’s a particularly intriguing approach that leverages modern electronics like a smartphone.

Thanks to [Quinor] for the tip!

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