The Cucumber House That LEGO Built

January 4, 2022 by Jenny List 19 Comments

How far are you prepared to go to build a novelty seasonal ornament? Maybe a gingerbread house, or perhaps a bit of 3D printed glitter to hang on your Christmas tree. For [The Brick Wall], none of this was enough. Instead what was needed was a complete LEGO automated factory that builds a log cabin, from the unlikely raw material of cucumbers.

What has been created is the LEGO equivalent of a timber mill, with the various machines served by an overhead gantry crane. The cucumbers are trimmed to square, before being transferred to a saw which cuts out the notches for the interlocking corners. Another saw line chops the sections around door and windows to length, and finally the roof planks are cut in a vertical saw. The video below is reported as taking 83 days to complete from planning to filming, and 18 cucumbers to build the house. We’re not sure the cucumber will become a regular building material, but we salute the effort involved here.

Though this may be one of the biggest we’ve seen, we’ve featured many LEGO machines making things before.

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Attack Of The Eighty-Foot String Shooter

January 1, 2022 by Brian McEvoy 24 Comments

String shooters are exciting because they adhere to the laws of physics in that peculiar way that makes us ask, “How?” and “Why?” After a bit of poking and prodding, maybe some light rope burn, we probably have a few ideas on how we’d make our own. [Nick Belsten] and [Joey Rain] saw some desktop models and thought, “Let’s make that puppy eighty feet long!” Video also embedded after the break.

Instead of hobby motors, flashlight batteries, and toy car wheels, they choose a washing machine motor and bike tires, then plug into an extension cord. The three-minute video isn’t a how-to build because once you start welding this kind of hardware together, you are already flying by the seat of your pants. You will see a front yard with people delighting in the absurdity of launching rope continuously over the treetops. There’s plenty of room for observing a wave traveling along the cord or polishing your fingernails in a hurry.

We want to make string shooters for the office and add our personal flavor, like lights or colored string so they’re safe to touch. If you have a unique twist on any physics experiments, drop us a line, but for insurance reasons, we’ll add that you should not make a chainsaw without a guide bar, aka, the forbidden chain-saber.

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The Safest Model Roller Coaster

December 2, 2021 by Brian McEvoy 9 Comments

[Jared Holladay] is a computer engineering student at the University of Cincinnati and a life-long roller coaster fanatic. A lot of people look at roller coasters as an exciting example of physics, like potential energy versus kinetic energy or inertia, and rightly so. [Jared] looks at them and wonders about the controls. Video also below and there is a feature-length explanation with more details. Some Hackaday readers and writers can identify the components, so we think his coaster model belongs here.

Like many folks in this field, he’s built K’nex models to get a handle on construction. He’s toured STEM shows with the tracks and undoubtedly wowed kids, adults, and physics teachers, but since he can speak to the programming, he is a triple threat. Now, he’s growing out of the toy construction plastic and moving into 3D printed parts with needle-fine tolerances.

His latest base is extruded aluminum, like what you’d want in a rigid CNC or printer. In addition to the industrial-grade surface, Rockwell Automation sent him a safety programmable logic controller, PLC, and a touchscreen HMI. Our fellows in the industry tell us those are far beyond the price scope of regular hobbyists. But fear not; your Arduino clones will suffice until you get your first grant.

The point of all the ruggedized hardware, aside from authenticity, is to implement safety features the same way you would in the industry. The redundant PLC connects to inductive prox sensors to check train speed and location. Other moving parts, like friction brakes, have sensors to report if there is a jam. After all, it’s no good if you can’t stop a train full of people. There are hundreds of things that can go wrong. Just ask [Jared] because he programmed on-screen indicators for all of them and classified them to let an operator know if they can keep the ride moving or if they need to call maintenance.

Not all homemade coasters are scale models, and some of the traditional ones have more than meets the eye.

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RC Minecraft Boat Patrols The Pool For Treasure

October 28, 2021 by Tom Nardi 5 Comments

Looking to recreate those relaxing Minecraft fishing sessions in real life, [electrosync] recently set out to 3D print himself a blocky remote controlled boat, complete with a similarly cubic occupant to ride in it. Each element of the build, from the oars to the bobber on the end of the fishing line, has been designed to look as faithful to the source material as possible. In fact, the whole thing is so accurate to the game that it’s almost surreal to see it rowing around the pool.

That said, some of the resemblance is only skin deep. For example the rowing action, though it appears to be properly synchronized to the boat’s movement through the water, is completely for show. A standard propeller and rudder arrangement under the boat provide propulsion and directional control, and [electrosync] notes its actually powerful enough to push the boat very near to its scale top speed from the game, despite the exceptionally poor hydrodynamics of what’s essentially just a rectangle.

Speaking of which, [electrosync] even went through the trouble of printing the hull in wood-fill PLA and coating it in polyester resin to make sure it was watertight. Granted he could have just made the boat out of wood in the first place, saving himself the nearly 60 hours it took to print the hull parts, but that would have been cheating.

Beyond the servos and motors that move the boat and the oars, [electrosync] had to give his 3D printed fisherman a considerable amount of dexterity. Servos embedded into the 3D printed parts allow “Steve” to rotate at the hips and raise and lower his arm. With a fishing pole slipped into a hole printed into the hand, he’s able to cast out his magnetic bobber and see whats biting.

We’ve actually seen quite a number of projects that allow virtual objects inside Minecraft to interact with the real world, but comparatively few efforts to recreate objects from the game’s blocky universe, so the change of pace is nice.

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Spider-Man Swings A Little Closer To Reality

October 26, 2021 by Matthew Carlson 5 Comments

Despite reading Hackaday daily and seeing the incredible things that people do, something comes along that just sort of blows you away every once in a while. Sometimes it’s just technically impressive, but often it is just, “I didn’t think that anyone would try this or even think of this.” [Joel Creates] is one such example with his Spider-Man wrist-mounted web-shooters.

Previously, [Joel] had built a web-slinging system based around a pressurized tank of hot glue worn like a backpack. What it lacked in miniaturization, it made up for in functionality. However, [JT of Build IRL] created a grappling-based Spider-Man system that fired ropes which got [Joel] thinking that perhaps the hot glue and the grappling system could be combined for a smaller overall package.

His solution is quite simple. Old CO2 cartridges filled with glue and a small nozzle drilled in are loaded into a quick-connect fitting. The hot glue is heated via an induction coil on a small tool belt before loading. A thermally insulating layer of paint and micro-vacuum spheres on the canister helps [Joel] place it in the wrist shooter without burning himself. A bike tire inflator with a lever-activated system forms the main assembly of the shooter. Using compressed air, the system fires a glob of hot glue at a surface and a metal web-shaped disk with holes and a rope attached to the blob of hot glue. As the glue rapidly cools, the metal disk provides a lot of surfaces for the adhesive to hang onto. Overall, the results are pretty impressive, but the engineering challenges make for an exciting journey. Everything from failed prototypes to failed power supplies seems to happen on this build.

Combined with some electromagnets, you could really have the whole spider package.

Thanks [Carson B] for sending this one in! Video after the break.

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You Can Build A Lego Rubik’s Cube

October 23, 2021 by Lewin Day 4 Comments

Rubik’s cubes are a popular puzzle — one found exciting or infuriating depending on your personal bent. [PuzzLEGO] has designed a LEGO Rubik’s cube, with the latest revision improving on flimsy earlier designs.

The first step was to design a core that would allow the cube to rotate freely without being too loose. This involved a lot of trial and error until [PuzzLEGO] found just the right combination of parts to do the job. From there, it was a matter of introducing the edge pieces and corner pieces without jamming everything up.

It took some experimenting to get everything moving together smoothly, but the end result is pretty impressive. It’s certainly not a build you’d use for speedcubing; the fragility meant that it took 20 minutes to solve just one face. [PuzzLEGO] hopes to make further improvements to increase playability.

If you want to replicate the feat, you’ll need plenty of little Lego bits and pieces, but it’s definitely a replicable build. Alternatively, consider using Lego to build a Rubik’s Solver, instead. Video after the break.

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A Promising Start For The Doritos Space Program

September 25, 2021 by Tom Nardi 11 Comments

Rocketry is tricky stuff, but as long as you’re not trying to get into space, the whole idea can basically be boiled down into a simple concept: if you put enough thrust behind it, anything can fly. At least, for awhile. It’s this basic premise that allows what hobbyists sometimes refer to as “Odd-Rocs” fly; these unusual objects might not be ideal rockets, but put a big enough motor in there, and it’ll get off the pad.

Recently, [concretedog] thought he’d try putting together his own oddball rocket, and set out to modify a Doritos STAX tube for powered flight. There’s plenty of precedent for turning Pringles tubes into rockets, but of course, that’s hardly surprising. After all, what’s a rocket if not a strong and lightweight cylinder? But the rounded triangular shape of the STAX tube promised to be an interesting change of pace. Plus it looked cool, so there’s that.

Turning the snack container into a rocket was actually pretty straightforward. To start with, [concretedog] sketched around the outside of the tube on a piece of paper, and then took a picture of that with his phone. That image was then brought into Inkscape, and turned into a vector file that he could fiddle around with in CAD.

Between the thin plywood cut on his laser and PETG loaded into his 3D printer, he was able to come up with a strong enough motor mount to take an Estes D12-5. He then created some fins to glue on the side, and a triangular nosecone. A simple recovery system was installed, and the whole thing was finished off with a Doritos-appropriate orange and black color scheme.

The unusual shape of the rocket meant simulating its flight characteristics on the computer wouldn’t work without custom software, so [concretedog] had to use the old school method of checking stability by swinging it around in a circle on a string. After trimming it out so it would orient itself properly on the tether, he was fairly sure it would fly straight under power. Sure enough, the video below shows the nacho cheese flavored rocket streaking skyward with impressive speed and stability.

It’s far from the most advanced model rocket we’ve seen recently, but we really appreciate the simplicity of this build. It’s a great reminder that fun doesn’t have to be high-tech, and that by following some basic construction principles, you can knock out a safe park flier rocket on a weekend.

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