Vastly Improved Servo Control, Now Without Motor Surgery

March 21, 2024 by Donald Papp 13 Comments

Hobby servos are great, but they’re in many ways not ideal for robotic applications. The good news is that [Adam] brings the latest version of his ServoProject, providing off-the-shelf servos with industrial-type motion control to allow for much, much tighter motion tracking than one would otherwise be limited to.

Modifying a servo no longer requires opening the DC motor within.

The PID control system in a typical hobby servo is very good at two things: moving to a new position quickly, and holding that position. This system is not very good at smooth motion, which is desirable in robotics along with more precise motion tracking.

[Adam] has been working on replacing the PID control with a more capable cascade-based control scheme, which can even compensate for gearbox backlash by virtue of monitoring the output shaft and motor position separately. What’s really new in this latest version is that there is no longer any need to perform surgery on the DC motor when retrofitting a servo; the necessary sensing is now done externally. Check out the build instructions for details.

The video (embedded just below) briefly shows how a modified servo can perform compared to a stock one, and gives a good look at the modifications involved. There’s still careful assembly needed, but unlike the previous version there is no longer any need to actually open up and modify the DC motor, which is a great step forward.

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Apple Vision Pro’s Secret To Smooth Visuals? Subtly Substandard Optics

March 21, 2024 by Donald Papp 32 Comments

The displays inside the Apple Vision Pro have 3660 × 3200 pixels per eye, but veteran engineer [Karl Guttag]’s analysis of its subtly blurred optics reminds us that “resolution” doesn’t always translate to resolution, and how this is especially true for things like near-eye displays.

The Apple Vision Pro lacks the usual visual artifacts (like the screen door effect) which result from viewing magnified pixelated screens though optics. But [Karl] shows how this effect is in fact hiding in plain sight: Apple seems to have simply made everything just a wee bit blurry thanks to subtly out-of-focus lenses.

The thing is, this approach of intentionally de-focusing actually works very well for consuming visual content like movies or looking at pictures, where detail and pixel-to-pixel contrast is limited anyway.

Clever loophole, or specification shenanigans? You be the judge of that, but this really is evidence of how especially when it comes to things like VR headsets, everything is a trade-off. Improving one thing typically worsens others. In fact, it’s one of the reasons why VR monitor replacements are actually a nontrivial challenge.

Ancient Instrument Goes Digital: The Digi-Gurdy

March 18, 2024 by Donald Papp 12 Comments

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

March 15, 2024 by Donald Papp 6 Comments

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

March 7, 2024 by Donald Papp 13 Comments

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

March 4, 2024 by Donald Papp 31 Comments

[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

February 22, 2024 by Donald Papp 7 Comments

[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” →