YouTuber Builds Onewheel With Tracks Instead And It’s Not Great

The one-wheel is a triumph of modern sensor and control technology. That made it possible to sense the acceleration and position of a platform with a single wheel, and to control that single wheel to keep the platform stable and level, even in motion. [RCLifeOn] has now taken that same concept and made it more hilarious by swapping out the wheel for a track.

The original idea was to build an electric snowboard, which worked just okay. Then, it morphed into a tank-based one-wheel instead. It’s a bit silly on the face of it, because a track is more stable than a wheel. That’s because instead of balancing on a small flattened spot of a tire, it’s got a wider, flatter footprint. But that means there’s no real need for balancing control as the track is statically stable.

The 3D-printed track assembly is driven by a powerful brushless motor via a gear drive for additional torque. Riding it is difficult on 48-volt power as it easily throws [RCLifeOn] off the board with its raw torque. At 24 volts, however, it was just barely ridable with some practice. But it was ultimately pretty terrible. It was either not moving at all, or jerking so hard that it was impossible to stay on the thing.

We’d like to see this concept tried again, perhaps with a rubber track and a more refined controller. Video after the break.

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Hackaday Links: November 12, 2023

Somebody must really have it in for Cruise, because the bad press just keeps piling up for the robo-taxi company. We’ve highlighted many of the company’s woes in this space, from unscheduled rendezvous with various vehicles to random acts of vandalism and stupid AI pranks. The hits kept coming as California regulators pulled the plug on testing, which finally convinced parent company General Motors to put a halt to the whole Cruise testing program nationwide. You’d think that would be enough, but no — now we learn that Cruise cars had a problem recognizing children, to the point that there was concern that one of their autonomous cars could clobber a kid under the right conditions. The fact that they apparently knew this and kept sending cars out for IRL testing is a pretty bad look, to say the least. Sadly but predictably, Cruise has announced layoffs, starting with the employees who supported the now-mothballed robo-taxi fleet, including those who had the unenviable job of cleaning the cars after, err, being enjoyed by customers. It seems a bit wrongheaded to sack people who had no hand in engineering the cars, but then again, there seems to be a lot of wrongheadedness to go around.

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Stripped Clock Wheel Gets A New Set Of Teeth, The Hard Way

If there’s one thing we’ve learned from [Chris] at Clickspring, it’s that a clockmaker will stop at nothing to make a clock not only work perfectly, but look good doing it. That includes measures as extreme as this complete re-toothing of a wheel from a clock. Is re-toothing even a word?

The obsessive horologist in this case is [Tommy Jobson], who came across a clock that suffered a catastrophic injury: a sudden release of energy from the fusee, the cone-shaped pulley that adjusts for the uneven torque created by the clock’s mainspring. The mishap briefly turned the movement into a lathe that cut the tops off all the teeth on the main wheel.

Rather than fabricate a completely new wheel, [Tommy] chose to rework the damaged one. After building a special arbor to hold the wheel, he turned it down on the lathe, leaving just the crossings and a narrow rim. A replacement blank was fabricated from brass and soldered to the toothless wheel, turned to size, and given a new set of teeth using one of the oddest lathe setups we’ve ever seen. Once polished and primped, the repair is only barely visible.

Honestly, the repaired wheel looks brand new to us, and the process of getting it to that state was fascinating to watch. If the video below whets your appetite for clockmaking, have we got a treat for you.

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Feeling The Heat: Railway Defect Detection

On the technology spectrum, railroads would certainly seem to skew toward the brutally simplistic side of things. A couple of strips of steel, some wooden ties and gravel ballast to keep everything in place, some rolling stock with flanged wheels on fixed axles, and you’ve got the basics that have been moving freight and passengers since at least the 18th century.

But that basic simplicity belies the true complexity of a railway, where even just keep keeping the trains on the track can be a daunting task. The forces that a fully loaded train can exert on not only the tracks but on itself are hard to get your head around, and the potential for disaster is often only a failed component away. This became painfully evident with the recent Norfolk Southern derailment in East Palestine, Ohio, which resulted in a hazardous materials incident the likes of which no community is ready to deal with.

Given the forces involved, keeping trains on the straight and narrow is no mean feat, and railway designers have come up with a web of sensors and systems to help them with the task of keeping an eye on what’s going on with the rolling stock of a train. Let’s take a look at some of the interesting engineering behind these wayside defect detectors.

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Differential Swerve Drive Is Highly Maneuverable

There are a variety of wheel designs out there that can provide for rotation and translation in various directions. The differential swerve drive, though, as demonstrated by [WildWillyRobots], uses regular wheels on a complex mount to achieve impressive directional flexibility.

The design uses a regular round wheel mounted on an axle, which has a gear on one end. This allows the wheel to be driven. The wheel and axle is mounted upon a circular carrier, which is then fitted with a pair of surrounding gears on bearings. Differentially driving these gears changes the way the drive behaves. With both gears driven in the same direction, the wheel rotates on its vertical axis to point in different directions. If both gears are driven in opposite direction, the wheel itself is driven. Relatively varying the speed of both gears allows the direction and drive of the wheel to be controlled. The result is a wheel that can rotate to any angle, and then be driven forwards or backwards as well.

Fitting a set of these wheels to a robot creates a highly maneuverable platform. As a bonus, it doesn’t have the drawback of poor grip that is common with various omniwheel-type designs.

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DIY Bike Wheels Welded With Rebar

[Liebregts] is working on a trike design, and needed a pair of wheels to go up front. Regular bicycle wheels wouldn’t do, as they’re not designed to work with a single-sided support. They also wanted to be able to mount disc brakes. Thus, they set about building a set of custom wheels to do the job.

The build began with a regular set of 20″ bike wheel rims with all the spokes taken out. A ring of steel rebar welded on the inner perimeter gave the rims more strength. A set of hubs and axles were then fabbed up with a welder and lathe, with provisions for bolting on disc brake components. Lengths of rebar were then welded in as non-adjustable spokes. Next, it was time for a coat of paint. Finally [Liebregts] mounted the tires and brakes, and called the job done.

Obviously, it is possible to buy wheels specifically for trike builds. However, [Liebregts] found it difficult to find exactly what they wanted, particularly where the disc brake option was concerned. The best option was a custom build.  The resulting wheels are obviously much heavier than traditional bike wheels, but they’re also likely a fair bit stronger, too. If you need to weigh down a tarpaulin, for example, these wheels might just do the trick.

We’ve seen some other crazy wheels on trikes before, too! Oh, and who says wheels need to be a full circle, anyway? Creativity will never cease to amaze!

How Fast Can You Spin A LEGO Wheel By Hand?

It’s not a question you ask yourself every day, but it’s one that the [Brick Experiment Channel] set out to answer: how fast can you spin a LEGO wheel by hand? In their typical way, they set about building an increasingly complex contraption to optimize for the very specific case of maximum RPM.

The build starts with a LEGO wheel fitted to an axle, supported in two LEGO Technic beams. A white flash mark is also attached onto a part of the axle for measuring the rotational speed with a photo-tachometer. A first attempt gets as fast as 1,700 RPM. Upgrades come thick and fast , and with a three-stage compound geartrain, the handcranked wheel reaches 6,300 RPM.  Adding a further stage introduces the problem that the plastic Technic axle begins to twist under the torque input by the hand.

Taking a new approach of pulling on a string to turn the wheel, the first attempt nets 8,300 RPM. Gearing pushes this further to 12,900 revs, but adding more gears again leads to the problem of axles bending under the strain. A bidirectional rope pull design helps, though, and the system reaches 13,100 RPM.

Some of the parts have been damaged thus far, but a rebuild with fresh parts that are nicely lubricated provides a huge boost. The now-slippery shafts run smoother and the wheel hits a blistering 19,300 RPM as the mechanism disassembles itself.

It’s a less complex pursuit than some earlier works from [Brick Experiment Channel], like the impressive pole climbing designs we’ve seen previously. However, it’s a video that shows the power of iterative design and the gains possible from that process.
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