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Hackaday Links: July 24, 2022

OK, maybe that won’t buff right out. NASA has released a more detailed analysis of the damage suffered by the James Webb Space Telescope in a run-in with a micrometeoroid, and has deemed the damage “uncorrectable”. Not that any damage to JWST is correctable, at least in the sense that the Hubble Space Telescope was able to be fitted with optics to fix its precisely-yet-inaccurately-ground main mirror. JWST is far too remote for a service call, so correctability in this case refers to a combination of what can be accomplished by tweaking the shape and position of the affected mirror segment, and what can be taken care of with image processing. The damage to segment C3, as well as damage to the other segments in a total of six collisions in the half year Webb has been on station, are assessed via “wavefront sensing”, which looks at how out of phase the light coming from each mirror segment is. The damage sounds bad, and it certainly must hurt for the techs and engineers who so lovingly and painstakingly built the thing to see it dinged up already, but in the long run, this damage shouldn’t hamper Webb’s long-term science goals.

In other space news, we hear that the Perseverance rover has taken its first chunk out of the ancient river delta in Jezero Crater. The rover has been poking around looking for something interesting to sample, but everything it tried out with its abrading tool was either too brittle, too hard to get at, or scientifically dull. Eventually the rover found a good spot to drill, and managed to bring up a 6.7-cm core sample. This makes the tenth core sample collected overall, and the first from the delta area, which is thought to have the best chance to contain evidence of ancient Martian life.

Closer to home, we’ve all likely heard of robotic surgery, but the image that conjures up doesn’t really comport with reality. Robot-assisted surgery is probably a better term, since surgical robots are generally just ultra-precise remote manipulators that are guided by a skilled surgeon. But if a study on surgery robot performance is any indication, the days of human surgeons might be numbered. The study compared accuracy and speed of both a human surgeon controlling a standard Da Vinci surgical robot and an autonomous version of the robot alone, using a depth camera for sensing. Using a standard surgical skills test, the autonomous system matched the human surgeons in terms of failures — thankfully, no “oopsies” for either — but bested the humans in speed and positional accuracy. It’ll probably be a while before fully autonomous surgeons are a thing, but we wouldn’t be betting against it in the long run.

Most readers will no doubt have heard the exciting news that Supercon will be back this year as an in-person event! Make sure you set aside the first weekend in November to make the pilgrimage to Pasadena — it’ll be great seeing everyone again after the long absence. But if you just can’t wait till November for an IRL con, consider dropping by SCALE 19X, coming up this week in Los Angeles. The Southern California Linux Expo is being held July 28 through 31, and features a ton of speakers, including a keynote by Vint Cerf. Hackaday readers can save 50% on tickets with promo code HACK.

And finally, as a lover of Easter eggs of all kinds, but specifically of the hidden message in software variety, we appreciated this ode to the Easter egg, the embedded artistry that has served as a creative outlet for programmers over the years. The article lists a few great examples of the art form, along with explaining why they’re actually important artifacts of the tech world and what they’re good for. We tried out a few of the ones listed in the article that we hadn’t heard of before; some hits, some misses, but they’re all appreciated. Well, most of them — the corporate rah-rah kind can bugger straight off as far as we’re concerned.

Automated musical instrument with LED array

ESP32 Is The Brains Behind This Art Installation

The ESP32 has enabled an uncountable number of small electronics projects and even some commercial products, thanks to its small size, low price point, and wireless capabilities. Plenty of remote sensors, lighting setups, and even home automation projects now run on this small faithful chip. But being relegated to an electronics enclosure controlling a small electrical setup isn’t all that these tiny chips can do as [Eirik Brandal] shows us with this unique piece of audio and visual art.

The project is essentially a small, automated synthesizer that has a series of arrays programmed into it that correspond to various musical scales. Any of these can be selected for the instrument to play through. The notes of the scale are shuffled through with some random variations, allowing for a completely automated musical instrument. The musical generation is entirely analog as well, created by some oscillators, amplifiers, and other filtering and effects. The ESP32 also controls a lighting sculpture that illuminates a series of LEDs as the music plays.

The art installation itself creates quite haunting, mesmerizing tunes that are illustrated in the video linked after the break. While it’s not quite to the realm of artificial intelligence since it uses pre-programmed patterns with some randomness mixed in, it does give us hints of some other projects that have used AI in order to compose new music.

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Pinewood Derby Scale Measures CG

If you suffer from nostalgia, you might remember carving a block of wood into a car, adding some wheels, and racing it against other contestants in a pinewood derby. Today’s derby is decidedly high tech though, and we were impressed with this car scale that also figures out the car’s center of gravity.

Based on an Arduino, of course, along with a pair of HX711 load cells. Why a pair? That’s how the device measures the center of gravity is by weighing the front and rear of the car separately.

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A Model Of Dry Humor

If you want to see a glorious combination of model bananas in a treehouse mixed with a lot of tongue-in-cheek humor, you will appreciate [Studson]’s build video. Video also after the break. He is making an homage to Donkey Kong 64 from 1999, which may be a long time ago for some folks’ memory (Expansion Pak). Grab a piece of your favorite banana-flavored fruit and sit tight for joke delivery as dry as his batch of baked bark.

The treehouse uses a mixture of found material and crafting supplies. In a colorful twist, all the brown bark-wielding sticks are green, while the decorative greenery came from a modeling store shelf. It all starts with a forked branch pruned from the backyard and a smooth-sided container lid that might make you look twice the next time you nuts are buying a bin of assorted kernels. If you thought coffee stirrers couldn’t be used outside their intended purpose, prepare to have your eyes opened, but remember to wear eye protection as some of the wood clippings look like they could achieve escape velocity. The key to making this look like an ape abode, and not a birdhouse, is the color choices and finishing techniques. Judging by the outcome and compared to the steps, making a model of this caliber is the sign of an expert.

If you wish to binge on wooden Donkey Kong, we can grant your desire, but if you prefer your treehouses life-sized, this may launch your imagination.

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Baby C-17 Sends Imaginations Soaring

The C-17 Globemaster III is a military cargo jet that can carry what their commercial counterparts can’t, to places those other planes can’t go. The people who keep these planes flying are proud of their capable airlifter, but it’s hard to show them off. Solution: build a scaled-down version more suitable for driving off base for a parade down Main Street and other community events.

While the real thing was built under an expensive and contentious military procurement process, the miniature was built with volunteer labor using castoff materials. The volunteer force included maintenance crew whose job is to know the C-17 inside and out. Combined with fabrication skills that comes with the job, the impressive baby plane faithfully copied many curvatures and details from full-sized originals. (Albeit with some alteration for its cartoony proportions.) Underneath are mechanicals from a retired John Deere Gator utility vehicle. They usually resemble a large golf cart except with a cargo bed and more rugged suspension. Basically they are to golf carts as a C-17 is to a 767. Amusingly, the little plane has its own rear loading ramp, superficially preserving the cargo-carrying capacity of the original Gator chassis.

Interior features continue, though the official picture gallery doesn’t show them. There is a flight deck with control panels and various sights and sounds to keep visitors entertained. Enough details were poured into the exhibit that some people had to ask if the little plane can fly, and the answer is a very definite no. The wings, and the engine pods mounted to them, are only for show carrying The Spirit of Hope, Liberty & Freedom. It is quite a long official name for such a short stubby thing.

We always love to admire impressively put-together miniatures, and not all projects require skill of aircraft mechanics. Like this very approachable miniature forklift project. But there are plenty of other projects whose skills put us in awe, like this remote-control car powered by a miniature V-10 engine.

[via The Museum of Flight]

3D-Printed Scale Model Of Perseverance Rover Seems As Complicated As The Real One

Sometimes the best way to figure out how something works is to make a model of it. 3D-modeling software makes it possible to do the job in silico, and sometimes that’s enough. But to really get inside the designer’s head, executing a physical model, like this quarter-scale RC-controlled Perseverance rover, is a great way to go.

If you’re looking for cutting-edge tech or groundbreaking design, this build will probably not light your fire. But a closer look will show not only great details about how JPL designs robots that can operate on Mars, but some great design and 3D-printing tips too. [Dejan]’s modeling process started with the 3D renderings of Perseverance available on the NASA website, which went into SolidWorks via Blender. [Dejan] was intent on capturing all the details of the rover, even those that ended up just for looks. But there’s plenty of functionality, too — the running gear looks and functions just like the six-wheel double-bogie design used on Perseverance, as well as Curiosity before it. This revealed an interesting fact that we didn’t previously realize — that the hull is suspended from a single pivot point on each side, while a linkage across the deck both prevents the body from pivoting and provides differential control of the drive bogies on either side of the rover.

The video below shows both the impressive amount of 3D printing needed to make all the model’s parts as well as the involved assembly process. It also shows the Arduino-controlled model being piloted around via radio control. There’s a lot to learn from this model, and [Dejan]’s craftsmanship here is top-notch too. We’ve seen such builds before from him, like this 3D-printed SCARA arm, a CNC hot-wire foam cutter, and an automated wire bender.

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Homebrew Slide Rule Gets Back To Mathematical Basics

In the grand scheme of things, it really wasn’t all that long ago that a slide rule was part of an engineer’s every day equipment. Long before electronic calculators came along, a couple of sticks of wood inscribed with accurate scales was all it took to do everything from simple multiplication to logarithms and trig functions.

While finding a slide rule these days isn’t impossible, it’s still not exactly easy, and buying one off the shelf isn’t as fun or as instructive as building one yourself. [JavierL90]’s slide rule build started, ironically enough, on the computer, with a Python program designed to graphically plot the various scales needed for the fixed sections of the slide rules (the “stators”) and the moving bit (the “slide”).  His first throught was to laser-engrave the scales, but the route of printing them onto self-adhesive vinyl stock proved to be easier.

With the scale squared away, work turned to the mechanism itself. He chose walnut for the wood, aluminum for the brackets, and a 3D-printed frame holding a thin acrylic window for the sliding cursor. The woodworking is simple but well-done, as is the metalwork. We especially like the method used to create the cursor line — a simple line scored into the acrylic with a razor, which was then filled with red inks. The assembled slide rule is a thing of beauty, looking for all the world like a commercial model, especially when decked out with its custom faux leather carry case.

We have to admit that the use of a slide rule is a life skill that passed us by, but seeing this puts us in the mood for another try. We might have to start really, really simple and work up from there.