Testing Carbon Fibre Reinforced Filament By Building An Over-Engineered Skateboard

December 3, 2019 by Danie Conradie 4 Comments

Advances in filaments for FDM 3D printers have come in leaps and bounds over the past few years, and carbon fibre (CF) reinforced filament is becoming a common sight. Robotics extraordinaire [James Bruton] got his hands on some CF reinforced PLA, and ended up building a completely over-engineered 3D printed skateboard. (Video, embedded below.)

[James] started by printing some test pieces with a 0.5 mm and a big 1.2 mm nozzle with and without the CF, which he subjected to cantilever deflection tests. The piece with CF was 20% stiffer than without.

[James] then built an extremely strong and cool looking skateboard deck with alternating section of the CF PLA and toughened PLA, totalling 2.7 kg of filament. It was extremely strong, so after bolting on a set of trucks and wheels, he did some mild riding at a local skate park, where it survived without any problems. He admits it was completely over-engineered, but points out in that the internal cavities in the deck is the perfect place for batteries on an electric long board.

Designing something from the ground up with the strength and weaknesses 3D printing in mind, leads to some very interesting and innovative designs, of which this is a perfect example, and we hope to see many more like it. We’ve featured a number of [James]’ project, including the remote controlled bowling ball he built for [Mark Rober] and his impressive OpenDog and Start Wars robots.

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US Air Force Says They’re Developing An Open Source Jet Engine; We Say Show Us The Design

November 27, 2019 by Tom Nardi 46 Comments

The economies of scale generally dictate that anything produced in large enough numbers will eventually become cheap. But despite the fact that a few thousand of them are tearing across the sky above our heads at any given moment, turbine jet engines are still expensive to produce compared to other forms of propulsion. The United States Air Force Research Laboratory is hoping to change that by developing their own in-house, open source turbine engine that they believe could reduce costs by as much as 75%.

The Responsive Open Source Engine (ROSE) is designed to be cheap enough that it can be disposable, which has obvious military applications for the Air Force such as small jet-powered drones or even missiles. But even for the pacifists in the audience, it’s hard not to get excited about the idea of a low-cost open source turbine. Obviously an engine this small would have limited use to commercial aviation, but hackers and makers have always been obsessed with small jet engines, and getting one fired up and self-sustaining has traditionally been something of a badge of honor.

Since ROSE has been developed in-house by the Air Force, they have complete ownership of the engine’s intellectual property. This allows them to license the design to manufacturers for actual production rather than buying an existing engine from a single manufacturer and paying whatever their asking price is. The Air Force will be able to shop ROSE around to potential venders and get the best price for fabrication. Depending on how complex the engine is to manufacture, even smaller firms could get in on the action. The hope is that this competition will serve to not only improve the design, but also to keep costs down.

We know what you’re thinking. Where is the design, and what license is it released under? Unfortunately, that aspect of ROSE seems unclear. The engine is still in development so the Air Force isn’t ready to show off the design. But even when it’s complete, we’re fairly skeptical about who will actually have access to it. Open Source is in the name of the project and to live up to that the design needs to be available to the general public. From a purely tactical standpoint keeping the design of a cheap and reliable jet engine away from potential enemy states would seem to be a logical precaution, but is at cross purposes to what Open Source means. Don’t expect to be seeing it on GitHub anytime soon. Nuclear reactors are still fair game, though.

[Thanks to Polymath99 for the tip.]

Electric Longboard Quick Build Using Off-The-Shelf Components.

November 22, 2019 by Danie Conradie 13 Comments

Building cool things completely from scratch is undeniably satisfying and makes for excellent Hackaday posts, but usually involve a few unexpected speed humps, which often causes projects to be abandoned. If you just want to get something working, using off-the-shelf modules can drastically reduce frustration and increase the odds of the project being completed. This is exactly the approach that [GreatScott!] used to build the 3rd version of his electric longboard, and in the process created an excellent guide on how to design the system and selecting components.

Previous versions of his board were relatively complicated scratch built affairs. V2 even had a strain gauge build into the deck to detect when the rider falls off. This time almost everything, excluding the battery pack, was plug-and-play, or at least solder-and-play. The rear trucks have built in hub motors, the speed controllers are FSESC’s (VESC software compatible) and the remote control system is also an off the shelf system. All the electronics were housed in 3D printed PETG housing, and the battery pack is removable for charging. We just hope the velcro holding on the battery pack doesn’t decide to disengage mid-ride.

The beauty of this video lies in the simplicity and how [GreatScott!] covers the components selection and design calculations in detail. Sometimes we to step back from a project and ask ourselves if reinventing is the wheel is really necessary, or just an excuse to do some yak shaving. Electric long boards are extremely popular at the moment, you can even make a deck from cardboard or make a collapsible version if you’re a frequent flyer.

Vintage Bike Gets Briggs And Stratton Power

November 20, 2019 by Lewin Day 18 Comments

eBay made the process of motorizing a bicycle popular, with cheap engines from China combined with a handful of parts to lace everything together. If your tastes are a little more vintage however, [Oliver]’s build might be more your speed.

Starting with a real Briggs and Stratton liberated from an old rotary tiller, this engine has legitimate vintage credentials. Looking resplendent in brown, it’s paired with a bike in a similar shade from yesteryear. Drive from the engine is transferred by belt to a jackshaft, which then sends power through a chain to the rear wheel. The belt tensioner serves as a rudimentary clutch, allowing the engine to be disconnected from the drivetrain when disengaged.

The retro components, combined with an appropriate color scheme, make this a wonderful cruiser that oozes style. While it’s probably not suited for downtown commuting due to its lack of a real clutch and noise, it would make a great ride for taking in some country roads on a sunny day. We’ve seen similarly styled e-bikes, too. Video after the break.

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The Ultimate Hacker’s Compact 4WD!

November 16, 2019 by Jenny List 3 Comments

If you’ve spent any time at one of the larger European hacker camps over the last few years you’ll have seen the invasion of little electric vehicles sporting hoverboard motors as an all-in-one propulsion system. German hackers, in particular, have incorporated them into the iconic Bobby Car children’s toy, and ca be seen whizzing around looking slightly incongruous as adults perched on transport designed for five-year-olds.

[Peter Pötzi] has created just such an electric Bobby Car, and his one is particularly well-executed with a 3D-printed steering column extender and four motors for full 4WD rather than the usual two. A steering wheel-mounted display has a neat enclosure, and is fed SPI from the ESP32 that runs the show via an RJ45 patch cable. Many of these builds use hoverboard motor controllers with hacked firmware, but this one instead takes a set of off-the-shelf VESCs. Control comes via a set of Xbox 360 trigger buttons mounted to the underside of the steering wheel.

The result is typically self-contained as are all the Bobby Car builds, with the added bonus of the extra power of four motors rather than two. We’re not so sure that 4WD gives it off-road capabilities though, but having seen these vehicles perform some nifty maneuvers in the past perhaps it’ll lend extra traction on corners.

This Is The Bike You Wanted Your Dad To Make You When You Were Eight Years Old!

November 16, 2019 by Jenny List 22 Comments

The ever-resourceful [Turbo Conquering Mega Eagle] has an excellent excuse for starting on projects, he’s building them for his kids and making videos. We’re not so sure his little motorcycle wasn’t built because Dad also wants to have a go though, because it seems he had quite a lot of fun testing it.

The build starts with a Chinese petrol conversion kit for a bicycle. There’s a little ~~two~~four-stroke motor and a basic chain drive to a large sprocket intended to fit on the opposite side of a bicycle wheel to the pedal sprocket. He uses a pair of pneumatic wheelbarrow wheels for which he makes a new bush and to which he welds the sprocket. These go into a fairly simple hardtail frame for which he makes a padded motorcycle seat, and from then on he’s ready to go.

The result is a rather cool little non-road-legal motorcycle that we suspect most readers will have a hankering to own. We’re not so sure about its seeming lack of brakes though. Judge for yourself, the video is below the break.

This isn’t the first home made small bike we’ve brought you, though it’s a lot safer than the first one.

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Bicycle Transforms Mid-Ride

November 13, 2019 by Bryan Cockfield 9 Comments

For those of us who were children in the late 80s and early 90s, we may have dreamed of one day owning a gigantic tractor trailer that could transform into a colossal fighting robot. Or of simply having a toy that could approximate this change from one form into another. As adults, though, we have come to realize that this is wishful thinking. That is, unless we decide to build this transforming bicycle.

What starts out as a slightly unusual-looking low rider-style bike effortlessly turns into a tall bike by means of a gas cylinder fixed to the bike’s rear triangle. The bike started out as a full suspension mountain bike, but the rear spring was removed to make room for this cylinder. The pivoting action of the rear triangle in a mountain bike is the key design element here: it allows the frame to change shape easily, in this situation when pushed by the cylinder. Adding some longer forks in the front and a coat of paint finishes the build.

This bike was entered in the Make It Move contest on Instrucables, and has gotten some pretty wide recognition so far. It’s a unique bicycle to be sure, and we’ve seen a few. From Russian offroad electric utility bicycles to bicycles that keep drivers from speeding down roads, there have been lots of interesting bike-based builds.

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