Grappling Hook Robot Swings Like Spiderman

August 28, 2021 by Al Williams 3 Comments

We’ll admit it is a bit of a gimmick, but [Adam Beedle’s] Spider-Bot did make us smile. The little robot can launch a “web” and use it to swing. It is hard to picture, but the video below will make it all clear. It can also use the cable to climb a wall, sort of.

The bot’s ability to fling a 3D printed hook on a tether is remarkable. Details are scarce, but it looks like the mechanism is spring-loaded with a servo motor to release it. Even trailing a bit of string behind it, the range of the hook is impressive and can support the weight of the robot when it winches itself up. There’s even a release mechanism that reminds us more of Batman than Spiderman.

If we were going full autonomous, we’d consider a vision system. On the other hand, you could probably tell a lot by the tension on the cable and some way to measure the angle of it coming out of the robot. If you come up with a practical use for any of this, we’d love to see it.

We’ve seen robots that fly, jump, and can climb walls before. We don’t remember one that swings like Tarzan.

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Resin print before and after paint injection.

Resin 3D Prints Get A New Look With Paint Injection

August 27, 2021 by Dan Maloney 20 Comments

As cool as resin-based 3D printers are, they’re not without their shortcomings. One sore point, especially for those looking to document their prints, is that the translucent resins often favored for stereolithography can make the finest details difficult to see. Injecting paint into the model is how [Andrew Sink] decided to attack this problem, and the results are pretty striking.

For sure, this isn’t a problem that everyone making resin prints is going to face. Some resins are nicely opaque, and the fine details of a print show up just fine. But transparent resins lend a nice look to some projects, and might benefit from [Andrew]’s technique. It’s pretty much as simple as it sounds: choose a hollow model — or modify an existing one — print it up in the usual way, and clean thoroughly inside and out with isopropanol before curing under UV. Using a curing station that can get UV light up into the voids is probably a smart idea.

To finish off, the cured model is injected with acrylic paint. Nothing special here, just craft store acrylic in a syringe. [Andrew] seemed to prefer a thicker paint; we don’t want to second guess, but intuitively a thinner paint would seem to have some advantages. In any case, be sure to provide adequate vent holes for the displaced air. The video below has a few before and after shots, and the technique really works well to show off surface detail. Plus it just plain looks cool.

This seems like a good technique to keep in mind, and might even work well for hollow FDM prints done with transparent filaments. Still on the fence about FDM vs. SLA? We can help with that.

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Can Metal Plated 3D Prints Survive 400,000 Volts?

August 25, 2021 by Dave Rowntree 12 Comments

It appears they can. [Ian Charnas] wanted his very own Thor Hammer. He wasn’t happy to settle on the usual cosplay methods of spray painting over foam and similar flimsy materials. He presents a method for nickel plating onto a 3D printed model, using conductive nickel paint to prepare the plastic surface for plating. In order to reduce the use of hazardous chemistry, he simplifies things to use materials more likely to be found in the kitchen.

As the video after the break shows, [Ian] went through quite a lot of experimentation in order to get to a process that would be acceptable to him. As he says, “after all, if something is worth doing, it’s worth over-doing” which is definitely a good ethos to follow. Its fairly hard to plate metals and get a good finish, and 3D printed objects are by their nature, not terribly smooth. But, the effort was well rewarded, and the results look pretty good to us.

But what about the 400 kV I hear you ask? Well, it wouldn’t be Thor’s hammer, without an ungodly amount of lightning flying around, and since [Ian] is part of a tesla coil orchestra group, which well, it just kinda fell into place. After donning protective chainmail to cover his skin, he walks straight into the firing line of a large pair of musical tesla coils and survives for another day. Kind of makes his earlier escapade with jet-powered roller skates look mundane by comparison.

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DIY Wigglegram Camera Lens Sends A Message To Big Photo

August 25, 2021 by Kristina Panos 10 Comments

Have you ever heard of a wigglegram? They are made by shooting multiple pictures at once using multiple lenses, and the the resulting stitched-together ‘gram is kind of a gif version of a stereographic image. It looks 3D, and it — well, it wiggles. The ones with a boomerang effect (i.e. a good loop) are especially prized.

Wigglegrams are often produced with Nishika quadrascopic cameras, which have naturally climbed in price to address the growing demand. Nishikas have four lenses and create four separate half-frame images by splitting the four photos across two frames of film. In contrast, [Joshua]’s DIY eye uses three plastic lenses from disposable film cameras to put three images onto a single frame of film.

The only real drawback is that the camera has to be close to the subject because the three lenses are so tightly packed. Another drawback is that there is no viewfinder while using this lens. There have to be divider walls between the three lenses to keep the images separate, and these walls have to extend all the way into the camera body. The Canon A-1’s viewfinder mirror does not allow for this, so [Joshua] pushed it up out of the way.

[Joshua]’s initial design approach to finding the ideal lens distance from the film plane was to do a bunch of calculations, but he ended up Goldilocks-ing it and iterating a bunch of times until it was just right. If you have a Canon SLR and want to build one of these, you’re in luck as far as the STLs go.

What else can you do with a bunch of old disposable cameras? Build your own flash, of course.

[via r/functionalprint]

Deceptively Simple Process Turns Bottles Into Filament

August 25, 2021 by Al Williams 68 Comments

If you know that most soda bottles are made from PET plastic, you’ve probably thought about how you could make filament from them and have an endless supply of cheap printing material. [Mr3DPrint] says he has a method and shares a few videos that make it look easy. We wonder if the quality of the filament is up to par with commercial products, but assuming the videos are accurate, it appears that the resulting filament gets the job done.

The details are a little sketchy, but it looks simple enough. THe first step is to get any indentations out of the bottle. He has several demonstrations of this some using pressurized air in the bottle and some without. In each case, though, a drill holds the bottle through the cap and spins it over a flame until the surface is smooth.

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Automatic Nut Sorter For A Tidy Workspace

August 23, 2021 by Al Williams 28 Comments

We all have that one drawer or box full of random hardware. You don’t want to get rid of anything because as soon as you do, that’s the one thing you’ll need. But, honestly, you’ll be lucky to find what you need in there, anyway. Enter [Mr. Innovative’s] nut sorting machine. As you can see in the video below, it will make order out of the chaos, at least for nuts.

You might think the device would need optical recognition software or some other high-tech mechanism. But, in fact, it is nothing more than a motor with a speed controller. The sorting is done by a plastic piece built like stairs. When a nut is too tall to fit under the next step, it slides out into the output hopper. You could probably turn the whole thing with a crank and no electricity at all if you wanted to.

Drilling out the shaft required a bit of machine tool usage, so this might not be a great weekend project without a lathe. Like many of the commenters on the video mentioned, we probably wouldn’t have used a rod holder as a rotating bearing, either, but for as little as something like this would probably operate, it is likely to last a fair amount of time. It would be easy to replace it or even affix a shaft to the motor with a coupler, sidestepping several issues.

Apparently, the device isn’t perfect. You do get some missorts. We imagine that’s from a larger nut pushing a smaller nut on the way to the hopper. The Thingiverse files seem to be missing, but this is something you’d probably adapt to your own design, anyway.

It isn’t as automated, but we’ve seen a gadget that can help sort drill bits, too. Sometimes you want to sort little parts by color, too.

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3D Printing Liquid Crystal

August 22, 2021 by Al Williams 7 Comments

If you think at all about liquid crystals, you probably think of display technology. However, researchers have worked out a way to use an ink-jet-like process to 3D print iridescent colors using a liquid crystal elastomer. The process can mimic iridescent coloring found in nature and may have applications in things as diverse as antitheft tags, art objects, or materials with very special optical properties.

For example, one item created by the team is an arrow that only appears totally green when viewed from a certain angle. The optical properties depend on the thickness of the material which, being crystalline, self-organizes. Controlling the speed of deposition changes the thickness of the material which allows the printer to tune its optical properties.

The ink doesn’t sound too exotic to create, although the chemicals in it are an alphabet soup of unpronounceable organic compounds. At least they appeared available if you know where to shop for exotic chemicals.

The iridescent coloring is common in nature, so art objects like butterfly wings are natural with this method. While inkjet printers aren’t common in the hacker community, they aren’t that hard to create, so this seems like it would be repeatable in a garage lab.

Liquid crystals have all kinds of interesting properties and we wonder if this material would help you print those sorts of things. If you want to experiment, we have seen a few hacked inkjet printers.

Thanks [jscotta] for the tip.