Building A One Wheel With Tracks

February 21, 2025 by Lewin Day 6 Comments

One-wheels use motion-tracking hardware and fine motor control to let you balance on a single wheel. That’s neat and all, but [Michael Rechtin] had another idea in mind—what if a one-wheel used a track instead?

The idea behind the track was to make the one-wheel more capable on surfaces where wheels simply can’t compete. The tracked drivetrain was largely 3D printed, including some massive gears that are supplemented by a big old 150 mm ball bearing which sits around the drive motor itself. If you love planetary gear trains with a 4:1 reduction, this project is for you. Carbon-fiber reinforced filament was used for many of the parts to give them some additional strength. Control is a little different than a traditional one-wheel, since the flat-bottomed track means lean controls won’t work. Instead, a wireless hand throttle was constructed to enable the rider to command the direction of travel.

It’s not easy to ride, but the one-track does actually work. It’s capable of crawling its way around on grass and snow quite well. There were some issues with the printed tracks and rollers, particularly when turning, but tweaks to round out the track profile helped solve that issue to a degree. There’s a reason we often use wheels instead of tracks, but somehow tracks are still just cool.

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Acoustic Engine Harnesses The Power Of Sound

February 21, 2025 by Dan Maloney 31 Comments

If you think sonic booms from supersonic aircraft are a nuisance, wait until the sky is full of planes propelled by up-scaled versions of this interesting but deafening audio resonance engine.

Granted, there’s a lot of work to do before this “Sonic Ramjet” can fly even something as small as an RC plane. Creator [invalid_credentials] came up with the idea for a sound-powered engine after listening to the subwoofers on a car’s audio system shaking the paint off the body. The current design uses a pair of speaker drivers firing into 3D printed chambers, which are designed based on Fibonacci ratios to optimize resonance. When the speakers are driven with a low-frequency sine wave, the chambers focus the acoustic energy into powerful jets, producing enough thrust to propel a small wheeled test rig across a table.

It’s fair to ask the obvious question: is the engine producing thrust, or is the test model moving thanks to the vibrations caused by the sound? [invalid_credentials] appears to have thought of that, with a video showing a test driver generating a powerful jet of air. Downloads to STL files for both the large and small versions of the resonating chamber are provided, if you want to give it a try yourself. Just be careful not to annoy the neighbors too much.

Thanks to [cabbage] for the tip via [r/3Dprinting].

Series Hybrid Semi-Trucks: It Works For Locomotives So Why Not?

February 18, 2025 by Maya Posch 66 Comments

The current Edison Motors semi-truck prototype. (Credit: Edison Motors)

Canadian start-up Edison Motors may not seem like much at first glance — consisting of fewer than two dozen people in a large tent — but their idea of bringing series hybrid technology to semi-trucks may just have wheels. The concept and Edison Motors’ progress is explained in a recent video by The Drive on Youtube, starting off with the point that diesel-electric technology is an obvious fit for large trucks like this. After all, it works for trains.

In a series hybrid, there are two motors: a diesel generator and an electric motor (diesel-electric). This was first used in ships in the 1900s and would see increasing use in railway locomotives starting in the early 20th century. In the case of Edison Motors’ current prototype design there is a 9.0 liter Scania diesel engine which is used solely as a generator at a fixed RPM. This is a smaller engine than the ~15 liter engine in a conventional configuration and also doesn’t need a gearbox.

Compared to a battery-electric semi-truck, like the Tesla Semi, it weighs far less. And unlike a hydrogen-fuel cell semi-truck it actually exists and doesn’t require new technologies to be invented. Instead a relatively small battery is kept charged by the diesel generator and power fed back into the battery from regenerative braking. This increases efficiency in many ways, especially in start-stop traffic, while not suffering a weight penalty from a heavy battery pack and being able to use existing service stations, and jerry cans of diesel.

In addition to full semi-trucks Edison Motors also works on conversion kits for existing semi-trucks, pick-up trucks and more. Considering how much of the North American rolling stock on its rail systems is diesel-electric, it’s more amazing that it would have taken so long for the same shift to series hybrid on its road. Even locomotives occasionally used direct-drive diesel, but the benefits of diesel-electric hybrids quickly made that approach obsolete.

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Decoy Killswitch Triggers Alarm Instead

February 17, 2025 by Bryan Cockfield 43 Comments

There are a few vehicles on the road that are targeted often by car thieves, whether that’s because they have valuable parts, the OEM security is easily bypassed, or even because it’s an antique vehicle that needs little more than a screwdriver to get started. For those driving one of these vehicles an additional immobilization feature is often added, like a hidden switch to deactivate the fuel pump. But, in the continual arms race between thieves and car owners, this strategy is easily bypassed. [Drive Science] hopefully took one step ahead though and added a decoy killswitch instead which triggers the alarm.

The decoy switch is placed near the steering column, where it would easily be noticed by a thief. Presumably, they would think that this was the reason the car wouldn’t start and attempt to flip the switch and then start the ignition. But secretly, the switch activates a hidden relay connected to the alarm system, so after a few seconds of the decoy switch activating, the alarm will go off regardless of the position of this switch. This build requires a lot of hiding spots to be effective, so a hidden method to deactivate the alarm is also included which resets the relay, and another killswitch which actually disables the fuel pump is also added to another secret location in the car.

As far as “security through obscurity” goes, a build like this goes a long way to demonstrate how this is an effective method in certain situations. All that’s generally needed for effective car theft prevention is to make your car slightly more annoying to steal than any other car on the road, and we think that [Drive Science] has accomplished that goal quite well. Security through obscurity is generally easily broken on things deployed on a much larger scale. A major European radio system was found to have several vulnerabilities recently thanks in part to the designers hoping no one would look to closely at them.

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All You Need To Make A Go-Kart, From Harbor Freight

February 7, 2025 by Jenny List 15 Comments

The many YouTube workshop channels make for compelling viewing. even if their hackiness from a Hackaday viewpoint is sometimes variable. But from time to time up pops something that merits a second look. A case in point is [BUM]’s go-kart made entirely from Harbor Freight parts, a complete but rudimentary vehicle for around 300 dollars. It caught our eye because it shows some potential should anyone wish to try their luck with the same idea as a Power Racer or a Hacky Racer.

The chassis, and much of the running gear comes courtesy of a single purchase, a four-wheeled cart. Some cutting and welding produces a surprisingly useful steering mechanism, and the rear axle comes from a post hole digger. Power comes from the Predator gasoline engine, which seems to be a favourite among these channels.

The result is a basic but serviceable go-kart, though one whose braking system can be described as rudimentary at best. The front wheels are a little weak and require some reinforcement, but we can see in this the basis of greater things. Replacing that engine with a converted alternator or perhaps an electric rickshaw motor from AliExpress and providing it with more trustworthy braking would result in possibly the simplest Hacky Racer, or just a stylish means of gliding round a summer hacker camp.

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Bicycle Adds Reliability With Second Chain

February 3, 2025 by Bryan Cockfield 70 Comments

Ignoring the International Cycling Union‘s mostly arbitrary rules for what a bicycle is “supposed” to look like (at least if you want to race), there are actually reasons that the bicycling world has standardized around a few common parts and designs. Especially regarding the drivetrain, almost all bikes use a chain, a freewheel, and a derailleur if there are gears to shift because these parts are cheap, reliable, and easy to repair. But if you’re off grid in a place like Africa, even the most reliable bikes won’t quite cut it. That’s why a group called World Bicycle Relief designed and built the Buffalo bicycle, and the latest adds a second gear with a unique freewheel.

Bicycling YouTuber [Berm Peak] takes us through the design of this bike in his latest video which is also linked below. The original Buffalo bicycle was extremely rugged and durable, with a rear rack designed to carry up to 200 pounds and everything on the bike able to be repaired with little more than an adjustable wrench. The new freewheel adds a second gear to the bike which makes it easier to use it in hilly terrain, but rather than add a complicated and hard-to-repair derailleur the freewheel adds a second chain instead, and the rider can shift between the two gears by pedaling backwards slightly and then re-engaging the pedals.

Of course a few compromises had to be made here. While the new freewheel is nearly as rugged as the old one, it’s slightly more complex. However, they can be changed quite easily with simple tools and are small, affordable, and easy to ship as well. The bike also had to abandon the original coaster brake, but the new rim brakes are a style that are also easy to repair and also meant that the bike got a wheel upgrade as well. Bicycles like these are incredibly important in places where cars are rare or unaffordable, or where large infrastructure needed to support them is unreliable or nonexistent. We’ve seen other examples of bicycles like these being put to work in places like India as well.

Thanks to [Keith] for the tip!

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New Frontiers For Nissan Leaf Motor And Battery

January 14, 2025 by Bryan Cockfield 9 Comments

Nissan started off with a massive lead in the electric vehicle industry — their Leaf was the first mass-market EV available and the highest-selling EV until 2020. But the company has begun to lag behind other automotive manufacturers and their more diverse, modern offerings. As an example, the Leaf still doesn’t have active cooling for its battery packs. On the plus side, though, these cars are pretty easy to work on and parts for them are widely available. This includes the battery pack and motor, which can be dropped in to other non-EV Nissan products like this Nissan Frontier.

For conversions using the Leaf battery pack and motor, [Paul] points out that it’s important to find the motor with the inverter and power distribution unit all integrated together, rather than sourcing them all separately since they don’t always mix-and-match well. There are several third-party parts available for getting these motors running in other applications, including a coupler to mate the motor to a transmission. However, this still needs some custom fabrication to properly attach to the Frontier’s drivetrain. With a new controller as well, the Frontier engine can be pulled, the Leaf engine dropped in, and the battery set into the bed and connected.

A followup video shows [Paul] driving his new EV down a neighborhood street, but it looks like there are still a few things to polish up before it’s ready to hit the open highway including a more robust housing for the battery. But, if donor vehicles can be found like a truck body and Leaf drivetrain components, this type of modification can be done for a surprisingly small cost. These EV batteries can also be put to work as home power banks as well.

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