3D-Printed RC Car Focuses On Performance Fundamentals

There are a huge number of manufacturers building awesome radio-controlled cars these days. However, sometimes you just have to go your own way. That’s what [snamle] did with this awesome 3D-printed RC car—and the results are impressive.

This build didn’t just aim to build something that looked vaguely car-like and whizzed around on the ground. Instead, it was intended to give [snamle] the opporunity to explore the world of vehicle dynamics—learning about weight distribution, suspension geometry, and so many other factors—and how these all feed into the handling of a vehicle. The RC side of things is all pretty straightforward—transmitter, receiver, servos, motors, and a differential were all off-the-shelf. But the chassis design, the steering, and suspension are all bespoke—designed by [snamle] to create a car with good on-road handling and grip.

It’s a small scale testbed, to be sure. Regardless, there’s no better way to learn about how a vehicle works on a real, physical level—you can’t beat building one with your own two hands and figuring out how it works.

It’s true, we see a lot of 3D printed RC cars around these parts. Many are built with an eye to robotics experimentation or simply as a learning exercise. This one stands out for its focus on handling and performance, and of course that nicely-designed suspension system. Video after the break.

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Bone Filament, For Printing Practice Bones

Of course there is bone-simulation filament on the market. What’s fun about this Reddit thread is all of the semi-macabre concerns of surgeons who are worried about its properties matching the real thing to make practice rigs for difficult surgeries. We were initially creeped out by the idea, but now that we think about it, it’s entirely reassuring that surgeons have the best tools available for them to prepare, so why not 3D prints of the actual patient’s bones?

[PectusSurgeon] says that the important characteristics were that it doesn’t melt under the bone saw and is mechanically similar, but also that it looks right under x-ray, for fluorscopic surgery training. But at $100 per spool, you would be forgiven for looking around for substitutes. [ghostofwinter88] chimes in saying that their lab used a high-wood-content PLA, but couldn’t say much more, and then got into a discussion of how different bones feel under the saw, before concluding that they eventually chose resin.

Of course, Reddit being Reddit, the best part of the thread is the bad jokes. “Plastic surgery” and “my insurance wouldn’t cover gyroid infill” and so on. We won’t spoil it all for you, so enjoy.

When we first read “printing bones”, we didn’t know if they were discussing making replacement bones, or printing using actual bones in the mix. (Of course we’ve covered both before. This is Hackaday.)

Thanks [JohnU] for the tip!

Bambu Connect’s Authentication X.509 Certificate And Private Key Extracted

Hot on the heels of Bambu Lab’s announcement that it would be locking down all network access to its X1-series 3D printers with new firmware, the X.509 certificate and private key from the Bambu Connect application have now been extracted by [hWuxH]. This application was intended to be the sole way for third-party software to send print jobs to Bambu Lab hardware as we previously reported.

The Bambu Connect app is a fairly low-effort Electron-based affair, with some attempt at obfuscation and encryption, but not enough to keep prying eyes out. The de-obfuscated main.js file can be found here (archived), with the certificate and private key clearly visible. These are used to encrypt HTTP traffic with the printer, and is the sole thing standing in the way of tools like OrcaSlicer talking with authentication-enabled Bambu Lab printers.

As for what will be the next steps by Bambu Lab, it’s now clear that security through obfuscation is not going to be very effective here. While playing whack-a-mole with (paying) users who are only interested in using their hardware in the way that they want is certainly an option, this might be a wake-up call for the company that being more forthcoming with their userbase would be in anyone’s best interest.

We await Bambu Lab’s response with bated breath.

New Bambu Lab Firmware Update Adds Mandatory Authorization Control System

As per a recent Bambu Lab blog post, its FDM printers in the X1 series will soon receive a firmware update that adds mandatory authentication for certain operations, starting with the firmware update on January 23rd for the aforementioned FDM printers. These operations include performing firmware upgrades, initiating a print job (LAN or cloud), remote video access and adjusting parameters on the printer. Using the printer directly and starting prints from an SD card are not affected.

As reasoning for this new feature Bambu Lab points to recent exploits that gave strangers access to people’s printers, though cheekily linking to an article on an Anycubic printer exploit. While admittedly a concern, this mostly affects internet-exposed printers, such as those that are tied into a ‘cloud’ account. Even so, LAN-based printing also falls under this new mandatory authentication system, with Bambu Lab offering a new tool called Bambu Connect for those who insist on using non-Bambu Lab branded software like OrcaSlicer. This allows for exported G-code files to be sent to a (property authenticated) Bambu Lab printer.

For those who do not wish to use this feature, not upgrading the firmware is currently the only recourse. Although this firmware update is only for X1-series printers, Bambu Lab promised that it’ll arrive for their other printers too in due time. While Bambu Lab printer owners consider installing the alternative X1 Plus firmware, the peanut gallery can discuss the potential security issues (or lack thereof) of an open Fluidd or similar UI on their LAN-connected, Klipper-based FDM printers.

Thanks to [mip] for the tip.

Building A 3D-Printed Strandbeest

The Strandbeest is a walking machine, a creation of the celebrated artist Theo Jansen. They can look intimidating in their complexity, but it’s quite possible to build your own. In fact, if you’ve got a 3D-printer, it can be remarkably straightforward, as [Maker 101] demonstrates.

The build relies on an Arduino Uno as the brains. It’s equipped with an L293D motor driver shield to run two DC gear motors which drive the walking assemblies. Power is courtesy of a 3-cell lithium-polymer battery. The chassis, legs, and joints are all 3D-printed, and rather attractively in complimentary colors, we might add.

Controlling this little Strandbeest is simple. [Maker 101] gave the Arduino an infrared sensor which can pick up signals from a simple IR remote control. It can be driven backwards and forwards or turned left and right. What’s more, it looks particularly elegant as it walks—a hallmark of a good Strandbeest design.

Design files are available online for the curious. We love a good Strandbeest build, and some can even be useful, too! Video after the break.
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Electromechanical 7-Segment Display Is High Contrast Brilliance

The seven-segment display is most well known in LED form, but the concept isn’t tied to that format. You can build a seven-segment display out of moving parts, too. [tin-foil-hat] has achieved just that with a remarkably elegant design.

As you might expect, the build relies heavily on 3D-printed components—produced in white and black plastic to create a high-contrast display. It’s a simple choice that makes the display easy to read in a wide variety of lighting conditions, and far less fussy than toying with LEDs and diffusers and all that.

Actuation of each display segment is achieved electromagnetically. Effectively, each segment behaves like a flip dot, with the orientation controlled by energizing one of two electromagnets per segment. Controlling the electromagnets is an ESP32, which is hooked up to the various segments via a Darlington transistor array, with multiplexing used to minimize the number of IO pins required. A shift register was also employed to let the microcontroller easily drive four of these electromechanical digits.

It’s a simple build, well explained—and the final result is aesthetically pleasing. We’ve seen a few builds along these lines before, albeit using altogether different techniques. Lots of different techniques, in fact! Video after the break.

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Fraens’ New Loom And The Limits Of 3D Printing

[Fraens] has been re-making industrial machines in fantastic 3D-printable versions for a few years now, and we’ve loved watching his creations get progressively more intricate. But with this nearly completely 3D-printable needle loom, he’s pushing right up against the edge of the possible.

The needle loom is a lot like the flying shuttle loom that started the Industrial Revolution, except for making belts or ribbons. It’s certainly among the most complex 3D-printed machines that we’ve ever seen, and [Fraens] himself says that it is pushing the limits of what’s doable in plastic — for more consistent webbing, he’d make some parts out of metal. But that’s quibbling; this thing is amazing.

There are mechanical details galore here. For instance, check out the cam-chain that raises, holds, and lowers arms to make the pattern. Equally important are the adjustable friction brakes on the rollers that hold the warp, that create a controlled constant tension on the strings.  (Don’t ask us, we had to Wikipedia it!) We can see that design coming in handy in some of our own projects.

On the aesthetic front, the simple but consistent choice of three colors for gears, arms, and frame make the build look super tidy. And the accents of two-color printing on the end caps is just the cherry on the top.

This is no small project, with eight-beds-worth of printed parts, plus all the screws, bearings, washers, etc. The models are for pay, but if you’re going to actually make this, that’s just a tiny fraction of the investment, and we think it’s going to a good home.

We are still thinking of making [Fraens]’s vibratory rock tumbler design, but check out all of his work if you’re interested in nice 3D-printed mechanical designs.

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