The Citadel is the King of K’nex Builds.

Following one’s passion can lead to amazing results. Sometimes this results in technological marvels; other times, one marvels at the use of the technology. An exemplary display of the latter is The Citadel.

Over the course of three years, redditor [Shadowman39] pieced together this monstrous K’nex structure. With over 17 different paths(!), 45 different elements, and over 40,000 parts, you would expect some meticulous planning to go into its construction — but that’s not the case! [Shadowman39] assembled it largely on the fly with only a few elements needing to be sketched out and only the main elevator proving to be troublesome. Three motors power the structure — one for the main elevator, one for the smaller lifts on the bottom, and one for the release gates.

This is an absolute leviathan hobby project. To satiate the obvious curiosity of anyone who stumbles across this picture, its intricacies can be seen in the video:

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K’nex whiteboard plotter

[Jerry] has been wanting to put together a whiteboard plotter for some time and just recently got around to building one.

The plotter draws pretty much about anything he can imagine on a white board measuring just shy of 2′ x 3′. The design first started off with a Basic Stamp board at the helm, which he sourced from another project he no longer had any use for. The Stamp worked for awhile, but eventually he ran into problems due to the board’s limited 128 bytes of program space. Needing a more robust micro controller, he switched to an Arduino mid-project, which he says runs the plotter far faster than the Stamp ever did.

The plotter uses a pair of stepper motors mounted on a horizontal platform situated above the whiteboard. Much like this large-format printer we featured earlier this week, the steppers vary the length of a pair of fishing lines, moving the pen precisely across the board.  As you can see in the image above, [Jerry] has been able to create some pretty intricate patterns with his plotter, and we imagine they will only get better with more refinement.

Be sure to check out his site for more details on his build process as well as several additional samples of the plotter’s capabilities.

Enlarged Miniature Forklift

How do you classify something that is gigantic and miniature at the same time? LEGO kit 850, from 1977 when it was known as an Expert Builder set, was 210 modular blocks meant to be transformed into a forklift nearly 140mm tall. [Matt Denton] scaled up the miniature pieces but it still produced a smaller-than-life forklift. This is somewhere in the creamy middle because his eight-year-old nephew can sit on it but most adults would demolish their self-esteem if they attempted the same feat.

[Matt] has been seen before building these modular sets from enlarged LEGO blocks, like his Quintuple-Sized Go-Kart. He seems to have chosen the same scale for the pieces and who wouldn’t? If you’re printing yourself a ton of LEGO blocks, it just makes sense to keep them all compatible. Isn’t combing all your sets into one mishmash the point after all? We’ll see what his nephew/co-host constructs after his uncle [Matt] leaves.

In the time-lapse video after the break, you can see how the kit goes together as easily as you would hope from home-made bricks. With that kind of repeatability and a second successful project, it’s safe to say his technique is solid and this opens the door to over-sized projects to which LEGO hasn’t published instructions.

Hackaday is bursting with LEGO projects, K’Nex projects, and even Erector set projects.

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I’ve Seen the Future and It’s Full of Freakin’ Huge Bricks

“Did you know you can 3D-print LEGO bricks that can actually be used as regular LEGO?”–me, in 2009

Those magical words made real to me the wonder that was 3D printing. It was a magical time! Everyone was 3D printing everything, though most of it wasn’t very good because the technology wasn’t there. But just as every technology goes through an evolution, the goalposts of coolness move on past what used to be remarkable to the new thing everyone’s talking about.

These days, no one is going to be more than mildly curious about your 3D-printed LEGO brick. Still, when you look at that uneven lump of plastic as being just one step in an evolution, it’s pretty momentous. What I’m saying is that we’re looking at a future that can be described in three words: Freakin’ Huge Bricks.

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Make a Tesla Coil Winding Rig with K’Nex

Instructables user [birdycrazy] built a winding rig from a PVC pipe and a bunch of K’Nex. He had recently started a Tesla coil project and needed an efficient way to wind the secondary coil. All of the designs for DIY winding rigs he found on the Internet required parts he didn’t have or simply cost a bunch of money. Then he realized he’d been building with K’nex a lot, and why not build a tool to help him?

He ended up investing only his K’nex elements and a length of 4” PVC pipe for the project. He used a K’nex 12V motor because it plugs in rather than requiring batteries. After the coil had been completely wound he set it to rotate the assembly over a period of several days while the varnish coating dried.

[birdycrazy] has several cool K’nex projects including a couple of automatic transmissions and a differential, all made with the toy. Also be sure to check out the K’nex whiteboard plotter, the Citadel monster K’nex castle, and the K’nex skeeball table we published in the past.

Join Us at the Greatest 3D Printing Festival on Planet Earth

Winter is hanging on like clinical depression, which means it’s that time again for the greatest 3D-printing festival on the planet Earth. It’s time for the Midwest RepRap Festival, next weekend, March 18-20th in Goshen, Indiana.

I can’t explain why, but for some reason the Midwest RepRap Festival is an oasis of building, doing, and hacking right in the middle of the county fairgrounds for Elkhart County, Indiana. It’s free for everyone to attend. The event isn’t choked with vendors, leaving the people who actually do stuff left to fight over a few picnic tables on the outskirts of the venue. It is, by far, the most community-centered event we go to every year.

If you’re wondering what you can expect at a 3D printer convention in the middle of nowhere, check out a few of the posts we’ve published from MRRF over the last few years. We’ve seen 3D printed waffles, resin casting with 3D printed molds, bizarre movement platforms, Bioprinting, and stuff from Lulzbot. That’s just the stuff that has deserved its own Hackaday post: we’ve seen the world’s largest 3D printed trash can, R2D2, battle droids (it’s even money if BB-8 is going to show up this year), a Printer made out of K’nex, and the most beautiful 3D printer we’ve ever seen. There was a T-shirt cannon powered by 300 psi shop air.

Every year I write a post announcing that we’ll be heading to MRRF next week, simultaneously praising the event as one of the greatest ‘maker’ and ‘DIY’ meetups, while pointing out the local WalMart parking lot has a place to park horse-drawn buggies. Both observations are true. For one weekend a year, Goshen, Indiana is the place everyone reading Hackaday should go to, and that is why we are once again proud to sponsor this glorious event.

3D Cable Robot Uses the Building as Its Exoskeleton.

There’s not much information about this commercial product, but it looks so interesting, we just had to share it. It doesn’t seem there is anything too magical happening here: some motors (presumably some type of servo or stepper with positioning feedback) some cables and pulleys, and an end effector of your choosing. Oh, and just some clever math to solve the inverse kinematics – not that inverse kinematics is all that easy! You can see the robot at work in the video after the break.

Most likely you’ve already seen the end results of such a three-dimensional cable driven system on your TV. If you’re a fan of most field sports, the SkyCam system is what’s used to deliver the stunning aerial shots that really put you into the game. We’ve covered this sort of mechanism before, but only in two dimensions. Usually we see the concept used as a white-board plotter like this extremely methodical Polargraph or one built with K’NEX.

We can’t help but wonder how this might be adapted into other situations?  Perhaps, you could use small light-weight cables (fishing line) and pulleys to make a living-room beer delivery system or TV remote retrieval claw?  Or could it become the mechanics of a really large format 3D printer? If any of you do rig up some sort of house-hold beverage fetching robot, be sure to let us know via the tipline.

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