3D Printable LED Diffusors

While you can get an LED matrix in any size or shape, the really cool looking ones that are perfect for low-res displays all have diffusors. When they come from a nameless Chinese factory, these diffusors are thin sheets of plastic set into an extruded plastic frame. Since [Jan] has a 3D printer, he figured a custom diffusor was just a few bits of filament and a SCAD file away.

The basis for this custom LED diffusor was a LoL Shield given to [Jan] by the creator at the recent 31C3 conference. This shield is really only just 126 LEDs, multiplexed and in an Arduino form factor, and that many LEDs were just too bright and indistinct next to each other. The plan for a 3D printed diffusor was hatched.

After taking a few measurements, a pair of OpenSCAD files were whipped up and printed out. Assembly consisted of pressing 126 tiny little white diffusors into a frame, but once everything was attached to the matrix, the results were worth it.

Check out the video below for the before and after, demonstrating what a few bits of plastic can do to a LED matrix.

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New 3D Printing Technique – Friction Welding

Even though 3D printers can fabricate complex shapes that would be nearly impossible to mill, they are not well suited to designs requiring bridging or with large empty spaces. To overcome this, [Scorch] has applied an easy plastic welding technique that works with both ABS and PLA. All you need is a rotary tool.

Friction welding” is the process of rubbing two surfaces together until the friction alone has created enough heat to join them. Industrially, the method is applied to joining large, metal workpieces that would otherwise require a time-consuming weld. In 2012, [Fran] reminded us of a toy from decades ago that allowed children to plastic weld styrene using friction. This modified method is similar to stick welding in that a consumable filler rod is added to the molten joint. Inspired by our coverage of [Fran], [Scorch] experimented and discovered that a stick of filament mounted into a Dremel works just as well for joining 3d prints.

That is all there is to it. Snip off a bit of filament, feed it into your rotary tool, and run a bead to join parts and shapes or do repairs. Friction welded plastic is shockingly strong, vastly superior to glued plastic for some joints. Another tool for the toolbox. See the videos below for [Scorch]’s demo.

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Ingenious Filament Spool Holder Keeps Your 3D Printer Printing

If you have a 3D printer, chances are, the company you bought it from skimped out on the design of their filament holder. It’s okay though, it’s not like having a toilet roll holder for your spool will result in failed prints… oh wait…

We don’t normally share projects like this because, gasp, it’s not really a hack, but this completely 3D printed filament spool holder by [Creative Tools] is actually quite amazing. It’s been designed to fit pretty much any kind of spool of filament you can imagine, as well as no spool at all. But what impresses us most is how the entire thing is 3D printed or makes use of 3D printer filament. No fasteners, no nothing.

Stuff like using rubber filament instead of grippy foot pads, and hard filament as the axles with 3D printed wheels for the quasi-thrust bearing used to support and rotate the spool.

All the parts are available over at Thingiverse.com — even if you don’t have a 3D printer, you might want to see the following video for some inspiring design tips on how to make such a clean and polished 3D printed assembly.

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Touching Light with Haptic Feedback

Many of us have gone on a stationary romp through some virtual or augmented scape with one of the few headsets out in the wild today. While the experience of viewing a convincing figment of reality is an exciting sensation in itself, [Mark Lee] and [Kevin Wang] are figuring out how to tie other senses into the mix.

The duo from Cornell University have built a mechanical exoskeleton that responds to light with haptic feedback. This means the wearer can touch the sphere of light around a source as if it were a solid object. Photo resistors are mounted like antenna to the tip of each finger, which they filed down around the edges to receive a more  diffused amount of light. When the wearer of the apparatus moves their hand towards a light source, the sensors trigger servo motors mounted on the back of the hand to actuate and retract a series of 3D printed tendons which arch upward and connect to the individual fingers of the wearer. This way as the resistors receive varying amounts of light, they can react independently to simulate physical contours.

One of the goals of the project was to produce a working proof of concept with no more than 100 dollars worth of materials, which [Mark] and [Kevin] achieve with some cash to spare. Their list of parts can be found on their blog along with some more details on the project.

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3D Printing Lock Picks

Over at the 23B hackerspace in Fullerton, CA, [Dano] had an interesting idea. He took a zip tie, and trimmed it to have the same profile of a lock pick. It worked. Not well, mind you, but it worked. After a few uses, the pick disintegrated, but still the concept of picks you can take through a TSA checkpoint was proven.

A few days after this demonstration, [C] realized he had a very fancy Objet 3D printer at work, and thought printing some pics out would be an admirable goal. After taking an image of some picks through the autotracer in Solidworks, [C] had an STL that could be printed on a fancy, high-end 3D printer. The printer ultimately used for these picks was a Objet 30 Pro, with .001″ layer thickness and 600dpi resolution. After receiving the picks, [C] dug out an old lock and went to town. The lock quickly yielded to the pick, and once again the concept of plastic lock picks was proven.

Although the picks worked, there were a few problems: only half the picks were sized appropriately to fit inside a lock. Two picks also broke within 15 minutes, something that won’t happen with traditional metal picks.

Still, once the models are figured out, it’s easy to reproduce them time and time again. A perfect lock pick design is then trivial, and making an injection mold becomes possible. They might still break, but they’ll be far easier to manufacture and simple to replace.

3D Printing Atomic Force Microscopy

[Andres] is working with an Atomic Force Microscope, a device that drags a small needle across a surface to produce an image with incredible resolution. The AFM can produce native .STL files, and when you have that ability, what’s the obvious next step? That’s right. printing atomic force microscope images.

The AFM image above is of a hydrogel, a network of polymers that’s mostly water, but has a huge number of crosslinked polymers. After grabbing the image of a hydrogel from an Agilent 5100 AFM, [Andres] exported the STL, imported it into Blender, and upscaled it and turned it into a printable object.

If you’d like to try out this build but don’t have access to an atomic force microscope, never fear: you can build one for about $1000 from a few pieces of metal, an old CD burner, and a dozen or so consumable AFM probes. Actually, the probes are going to be what sets you back the most, so just do what they did in olden times – smash diamonds together and look through the broken pieces for a tip that’s sufficiently sharp.

3D Printing Without Support

3D printing is getting better every year, a tale told by dozens of Makerbot Cupcakes nailed to the wall in hackerspaces the world over. What was once thought impossible – insane bridging, high levels of repeatability, and extremely well-tuned machines – are now the norm. We’re still printing with supports, and until powder printers make it to garages, we’ll be stuck with that. There’s more than one way to skin a cat, though. It is possible to print complex 3D objects without supports. How? With pre-printed supports, of course.

[Markus] wanted to print the latest comet we’ve landed on, 67P/Churyumov–Gerasimenko. This is a difficult model for any 3D printer: there are two oversized lobes connected by a thin strand of comet. There isn’t a flat space, either, and cutting the model in half and gluing the two printed sides together is certainly not cool enough.

To print this plastic comet without supports, [Markus] first created a mold – a cube with the model of the comet subtracted with a boolean operation. If there’s one problem [Markus] ran into its that no host software will allow you to print an object over the previous print. That would be a nice addition to Slic3r or Repetier Host, and shouldn’t be that hard to implement.