Transportation Hacks

1614 Articles

Fundamentals Of FMCW Radar Help You Understand Your Car’s Point Of View

October 19, 2024 by 3 Comments

Pretty much every modern car has some driver assistance feature, such as lane departure and blind-spot warnings, or adaptive cruise control. They’re all pretty cool, and they all depend on the car knowing where it is in space relative to other vehicles, obstacles, and even pedestrians. And they all have another thing in common: tiny radar sensors sprinkled around the car. But how in the world do they work?

If you’ve pondered that question, perhaps after nearly avoiding rear-ending another car, you’ll want to check out [Marshall Bruner]’s excellent series on the fundamentals of FMCW radar. The linked videos below are the first two installments. The first covers the basic concepts of frequency-modulated continuous wave systems, including the advantages they offer over pulsed radar systems. These advantages make them a great choice for compact sensors for the often chaotic automotive environment, as well as tasks like presence sensing and factory automation. The take-home for us was the steep penalty in terms of average output power on traditional pulsed radar systems thanks to the brief time the radar is transmitting. FMCW radars, which transmit and receive simultaneously, don’t suffer from this problem and can therefore be much more compact.

Continue reading “Fundamentals Of FMCW Radar Help You Understand Your Car’s Point Of View” →

Self-Portaging Canoe Is Part Bicycle

October 19, 2024 by 10 Comments

Normally when making a long voyage in a canoe, an adventurer would paddle the vessel as far as possible and then “portage”, or carry, the canoe over the short sections of land separating the bodies of water. Portaging is a lot of work, though, since canoes generally aren’t particularly light or designed for traveling over land. To solve this problem, [Ben] is modifying his home-built canoe with some interesting parts to make it into an amphibious vehicle which can much more easily traverse land.

The wheels for the amphibious craft come from BMX bicycles, which have much smaller wheels as well as more robust frames when compared to more traditional bicycles. The rear of the canoe was modified to use a go-kart axle with two driven wheels. An additional set of cranks mounted outboard drive a custom-built paddle to propel the boat when traveling on water. The frame borrows heavily from recumbent bicycle design and includes a similarly comfortable seat, with steering handled by a wheel at the front when traveling on land and a rudder at the rear when traveling over water.

[Ben] intends to take this unique vehicle on a cross-country trip across Scotland, with the first part of the adventure on water via the Caledonian Canal and the return trip on land via the Great Glen Way. Hopefully, there’s no actual portaging required for his trip as the bike components add a tremendous amount of weight to the boat. [Ben] he even added a sail that could theoretically be used in either mode. We’ll be keeping watch for his next videos showing his adventure, and in the meantime daydreaming about other unique bikes that let you travel where bikes normally can’t.

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A vaguely boat-shaped vehicle with three wheels and a mast. It sits in a barren-looking plain with short mountains in the distance

Sailing The High Steppes

October 10, 2024 by 29 Comments

Sails typically bring to mind the high seas, but wind power has been used to move craft on land as well. Honoring this rich tradition, [Falcon Riley] and [Amber Word] decided to sail across Mongolia in “Moby the Land Sailing vessel.”

Built in a mere three days from $200 in materials they were able to scrounge up the week before, the cart served as their home for the 300 km (~186 mi) journey across the Mongolian countryside. Unsurprisingly, bodging together a sailing vessel in three days to traverse uneven terrain led to a failed weld to the front tire, but a friendly local lent a hand to get them back on the road.

Built mostly out of plywood, the fully-laden cart tipped the scales at 225 kg (500 lbs) and could still be towed by hand. Under sail, however, they managed 70 km in one particularly windy day. They covered the distance in 46 days, which isn’t the fastest way to travel by any means, but not bad given the quick build time for this house on wheels. We suspect that a more lightweight and aerodynamic build could yield some impressive results. Maybe it’s time for a new class at Bonneville?

If you want to learn to sail in your own landlocked region, maybe learn a bit first? Instead you might want to build an autonomous sailing cart or take a gander at sailing out of this world?

[Thanks to Amber for stopping by to suggest some corrections!]

3D Printed Bearings With Filament Rollers

October 9, 2024 by 24 Comments

Commodity bearings are a a boon for makers who to want something to rotate smoothly, but what if you don’t have one in a pinch? [Cliff] of might have the answer for you, in the form of 3D printed bearings with filament rollers.

With the exception of the raw filament rollers, the inner and outer race, roller cage and cap are all printed. It would also be possible to design some of the components right into a rotating assembly. [Cliff] makes it clear this experiment isn’t about replacing metal bearings — far from it. Instead, it’s an inquiry into how self-sufficient one can be with a FDM 3D printer. That didn’t stop him from torture testing the design to its limits as wheel bearings on an off-road go-cart. The first version wasn’t well supported against axial loads, and ripped apart during some more enthusiastic maneuvers.

[Cliff] improved it with a updated inner race and some 3D printed washers, which held up to 30 minutes of riding with only minimal signs of wear. He also made a slightly more practical 10 mm OD version that fits over an M3 bolt, and all the design files are downloadable for free. Cutting the many pieces of filament to length quickly turned into a chore, so a simple cutting jig is also included.

Let us know in the comments below where you think these would be practical. We’ve covered some other 3D printed bearing that use printed races, as well as a slew bearing that’s completely printed. Continue reading “3D Printed Bearings With Filament Rollers” →

Soaring At Scale: Modular Airship Design

October 8, 2024 by 31 Comments

If you’re looking for an intriguing aerial project, [DilshoD] has you covered with his unique twist on modular airships. The project, which you can explore in detail here, revolves around a modular airship composed of individual spherical bodies filled with helium or hydrogen—or even a vacuum—arranged in a 3x3x6 grid. The result? A potentially more efficient airship design that could pave the way for lighter-than-air exploration and transport.

The innovative setup features flexible connecting tubes linking each sphere to a central gondola, ensuring stable expansion without compromising the airship’s integrity. What’s particularly interesting is [DilshoD]’s use of hybrid spheres: a vacuum shell surrounded by a gas-filled shell. This dual-shell approach adds buoyancy while reducing overall weight, possibly making the craft more maneuverable than traditional airships. By leveraging materials like latex used in radiosonde balloons, this design also promises accessibility for makers, hackers, and tinkerers.

Though this concept was originally submitted as a patent in Uzbekistan, it was unfortunately rejected. Nevertheless, [DilshoD] is keen to see the design find new life in the hands of Hackaday readers. Imagine the possibilities with a modular airship that can be tailored for specific applications. Interested in airships or modular designs? Check out some past Hackaday articles on DIY airships like this one, and dive into [DilshoD]’s full project here to see how you might bring this concept to the skies.

Vehicle-To-Everything: The Looming Smart Traffic Experience

October 7, 2024 by 48 Comments

Much of a car’s interaction with the world around it is still a very stand-alone, analog experience, regardless of whether said car has a human driver or a self-driving computer system. Mark I eyeballs or equivalent computer-connected sensors perceive the world, including road markings, traffic signs and the locations of other road traffic. This information is processed and the car’s speed and trajectory are adjusted to ideally follow the traffic rules and avoid unpleasant conversations with police officers, insurance companies, and/or worse.

An idea that has been kicked around for a few years now has been to use wireless communication between cars and their environment to present this information more directly, including road and traffic conditions, independent from signs placed near or on the road. It would also enable vehicle-to-vehicle communication (V2V), which somewhat like the transponders in airplanes would give cars and other vehicles awareness of where other traffic is hanging out. Other than V2V, Vehicle-to-Everything (V2X) would also include communication regarding infrastructure (V2I), pedestrians (V2P) and an expansive vehicle-to-network (V2N) that gives off strong Ghost in the Shell vibes.

Is this is the future of road traffic? The US Department of Transport (DOT) seems to think that its deployment will be a good thing, but V2X has been stuck in regulatory hurdles. This may now change, with the DOT releasing a roadmap for its deployment.

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3D Printed Hydrofoil Goes From Model Scale To Human Scale With Flight Controller

October 6, 2024 by 5 Comments

Hydrofoils have been around for several decades, but watching a craft slice through the water with almost no wake never get old. In the videos after the break, [rctestflight] showcases his ambitious project: transforming a standup paddleboard into a rideable hydrofoil with active stabilization.

Unlike conventional electric hydrofoil boards that depend on rider skill for balance, [rctestflight] aims to create a self-stabilizing system. He began by designing a small-scale model, complete with servo-controlled ailerons and elevators, dual motors for differential thrust, and a dRehmFlight flight controller. A pair of sonar sensors help the flight controller maintain constant height above the water. The wings are completely 3D printed, with integrated hinges for flight control surfaces slots for wiring and control components. It’s better suited for 3D printing than RC aircraft since it’s significantly less sensitive to weight, allowing for more structural reinforcement. The small scale tests were very successful and allowed [rctestflight] to determine that he didn’t need the vertical stabilizer and rudder.

The full-sized version features a scaled up wing, larger servos and motors attached to an 11-foot standup paddleboard — minus its rear end — mounted on commercially available e-foil booms. A foam battery box stores a hefty LiFePO4 battery, while the electronics from the smaller version are repurposed here. Despite only catching glimpses of this larger setup in action at the end of the video, it promises an excitingly smooth lake ride we would certainly like to experience.

We’ve seen several 3D printed hydrofoils around here, but this promised to be the largest successful attempt. Don’t fail us [Daniel].

Continue reading “3D Printed Hydrofoil Goes From Model Scale To Human Scale With Flight Controller” →