Ikea have been known for years as a purveyor of inexpensive yet stylish homewares, but it’s fair to say that sometimes their affordability is reflected in their insubstantial construction. Such is the case with the Sjöpenna lamp, whose construction relies on rubber bands. On [Tony]’s lamp these bands degraded with age, causing it to fall apart. The solution? A set of cleverly-designed laser-cut clips to replace them.
The challenge to replacing a stretchy material with a rigid one is that it must have enough ability to bend without snapping as it is put in place. For this he selected PETG, with 0.04″ (about 1 mm thick) hitting the sweet spot. His photos demonstrate with some green tape added for visibility, how the clip bends backwards just far enough to fit over where the rubber band once located, and then flips back neatly to hold it all in place.
If you have a collapsing Ikea lamp then this will be just what you need, but this hack goes further than that. A frequent requirement for repairs is some kind of clip, because clips are always the first to break, This technique for laser cutting them is a handy one to remember, next time your design needs a springy bit of plastic.
[Exposed Wire] is a huge fan of YouTube and consumes a lot of content. If that sounds familiar, maybe you should build a dedicated YouTube box, too. You get to push buttons, there’s LEDs, and you can take a break from other screens to look at this one for a while. [Exposed Wire] wanted to make it easier to watch the latest videos from their favorite creators, but we would argue that this is more fun, too.
The Rasberry Pi 4 inside checks every five minutes for new videos by keeping track of the creator’s total number of videos in a text file and doing a comparison. If one of the channels has a new video, then the corresponding LED lights up and the new video’s URL is linked to the button. Press the button and the Raspi opens the browser, goes the the URL, maximizes the video, turns off the LED, and updates the video count in the text file.
We like the construction job here. The 1/4″ MDF walls are connected by 3D-printed L-brackets in PETG. At first, [Exposed Wire] mounted the LEDs and buttons to a PCB, but that was really fiddly so they printed panels instead. Combined with the bracket around the screen, the finished build looks good. Check out the build montage after the break.
[Mark] printed a partial shade in PETG that is made to sit directly on the bulb itself. The back of the shade is open, allowing light to spill out from behind while the front of the bulb is shielded, making it easier on the eyes. The result is pretty nifty, as you can see here. It sits in the center of the 600 mm tall lamp, which takes up most of the build volume of his self-made CoreXY-based printer, the UMMD.
Just how tight are the manufacturing tolerances of modern FDM printer filament. Inquiring minds want to know, and when such minds are attached to handy fellows like [Thomas Sanladerer], you end up with something like this home-brew filament measurement rig to gather the data you seek.
The heart of this build is not, as one might assume, some exotic laser device to measure the diameter of filament optically. Those exist, but they are expensive bits of kit that are best left to the manufacturers, who use them on their production lines to make sure filament meets their specs. Rather, [Thomas] used a very clever homemade device, which relies on a Hall effect sensor and a magnet on a lever to do the job. The lever is attached to a roller bearing that rides on the filament as it spools through the sensor; variations in diameter are amplified by the lever arm, which wiggles a magnet over the Hall sensor, resulting in a signal proportional to filament diameter.
The full test rig has a motor-driven feed and takeup spools, and three sensors measuring across the filament in three different spots around the radius; the measurements are averaged together to account for any small-scale irregularities. [Thomas] ran several different spools representing different manufacturers and materials through the machine; we won’t spoil the results in the video below, but suffice it to say you probably have little to worry about if you buy from a reputable vendor.
When we see a filament sensor, it’s generally more of the “there/not there” variety to prevent a printer from blindly carrying on once the reel is spent. We’ve seen a few of those before, but this is a neat twist on that concept.
[Stefan] is always trying to make stronger 3D prints. Annealing can strengthen prints, but often at the expense of the part’s exact dimensions. His latest approach is to embed the prints in plaster and then anneal in an attempt to fuse the plastic together without changing its shape or size. Did it work? See for yourself in the video below.
He’s done a lot of work we’ve taken note of before where he measures the strength of parts after different post-processing steps. His test plastic parts used both PLA and PETG.
The biggest problem with fused deposition 3D prints is that while the layers should stick together, they aren’t the same as a solid piece of plastic you would get from, say, injection molding. You can anneal plastic using moderate heat, but it is likely to cause the part to deform or change size. [Free Spirit 1] has a solution for this. Using a powdered salt, the part is packed on the inside and out and put in an oven. The results in the video below look really impressive.
In addition to making the part look solid and — we assume — adding strength, the resulting prints are also water- and gas-tight which was the purpose of the effort. That alone would make the technique worthwhile.
The only thing we noticed is that the part has to have access to hold the salt. Anything not supported would be subject to deformation. However, the ground-up salt is so fine that it should be relatively easy to fill in most parts and, of course, print with 100% infill to avoid hollow internal areas.
[Free spirit 1] used a coffee grinder to get the salt powder, but apparently you can buy “flour salt.” We wondered if other powders might work well, too. Apparently, sand didn’t work out, perhaps because the salt dissolves out in water, so whatever you use, it should probably dissolve in something that won’t attack your plastic.
Annealing isn’t a new idea, and we’d love to see some objective tests on this new method.
While hackers and makers have a tendency to focus on functionality above all else, that doesn’t mean there isn’t room for some visual flair. A device that works well and looks good will always be more impressive than the bare bones approach, but the extra time and money it usually takes to polish up the visual component of a build means it’s often overlooked. Which is exactly what [Jay Doscher] wanted to address with his Mil-Plastic project.
On the surface, the Mil-Plastic is yet another entry in the rapidly growing and often ill-defined world of cyberdecks: custom computing devices that forgo the standard laptop and desktop dichotomy and instead explore the road not taken by mainstream consumer electronics. To that end, it’s a solid build more than worthy of praise. But more than that, it’s also a lesson on how 3D printing and some clever design can create a truly impressive visual for little more than the cost of a spool of PLA.
The Mil-Plastic, as the name implies, looks like it was pulled from a Humvee or an Abrams tank. While the gorgeous olive green PETG filament that [Jay] has stumbled upon certainly helps, his eye for detail and design chops aren’t to be underestimated. He’s given the case a rugged and armored look that simply screams “Your Tax Dollars At Work”, complete with faux cooling fins running along the back and a generous application of low-profile stainless steel fasteners. We’ve taken a close look at the decadence of military engineering in the past, and the Mil-Plastic could hang with the best of them.
Most importantly, [Jay] has given us all the tools and information we need to recreate the look on our own terms. You don’t have to be in the market for yet another Raspberry Pi gadget to appreciate the Mil-Plastic; the design can serve as the backbone for whatever you happen to be building. The printed case not only looks impressive, but can easily be modified and expanded as needed.