Most 3D printer filament soaks up water from the air, and when it does, the water passing through the extruder nozzle can expand, bubble, and pop, causing all kinds of mayhem and unwanted effects in the print. This is why reels come vacuum sealed. Some people 3D print so much that they consume a full roll before it can soak up water and start to display these effects. Others live in dry climates and don’t have to worry about humidity. But the rest of us require a solution. To date, that solution has been filament dryers, which are heated elements in a small reel-sized box, or for the adventurous an oven put at a very specific temperature until the reel melts and coats the inside of the oven. The downside to this method is that it’s a broad stroke that takes many hours to accomplish, and it’s inefficient because one may not use the whole roll before it gets soaked again.

In much the same way that instant water heaters exist to eliminate the need for a water heater, [3DPI67] has a solution to this problem, and it involves passing the filament through a small chamber with a heating element and fan circulating air. The length of the chamber is important, as is the printing speed, since the filament needs to have enough time in the improvised sauna to sweat out all its water weight. The temperature of the chamber can’t get above the glass transition temperature of the filament, either, which is another limiting factor for the dryer. [3DPI67] wrote up a small article on his improvised instant filament heater in addition to the video.

So far, only TPU has been tested with this method, but it looks promising. Some have suggested a larger chamber with loops of filament so that more can be exposed for longer. There’s lots of room for innovation, and it seems some math might be in order to determine the limits and optimizations of this method, but we’re excited to see the results.

Riley, an 8 lb pug, has more beauty than brains, and a palate as unrefined as crude oil. While we hate criticizing others’ interests and tastes, his penchant for eating cat poop needed to stop. After a thorough exploration of a variety of options, including cat food additives that make its excrement taste worse (HOW? WHY? Clearly taste wasn’t the issue!), automatic litter boxes that stow the secretions, and pet doors that authenticate access to the room with the litter box, [Science Buddies] eventually settled on a solution that was amenable to all members of the family.

The trick was in creating a door mechanism with a blacklist of sorts rather than a whitelist. As the cat didn’t like to push the door open itself, the solution needed to have the pet door open by default. A magnet on Riley’s collar would trip a sensor attached to an Arduino that would control servos to swing the door shut immediately if he attempted to access the defecated delights. Of course safety was a consideration with the door swinging in Riley’s face.

We’ve covered a few pet screeners, including one for the same purpose that used IR sensors (but a much bigger dog also named Riley), and a flock of solutions for chickens. We’ve also seen [Science Buddies] in previous posts, so they’re not on the tips line blacklist.

While multicolor printing eliminates painting steps and produces vibrant objects, there are two significant downsides; filament consumption and print time. A single-nozzle filament printer needs to switch from one color to another, and doing so involves switching to the other filament and then purging the transition filament that contains a mixture of both colors, before resuming the print with the clean new color.

[teachingtech] tests out a variety of methods for reducing print time and waste. One surprising result was that purging into the infill didn’t result in significant savings, even when the infill was as high as 50%. Things that did have a positive effect included reducing the amount of purge per transition based on light to dark color changes, and printing multiple copies at once so that even though the total amount of waste was the same as a single part, the waste per part was reduced.

All of the tests were with the same model, which had 229 color changes within a small part, so your mileage may vary, but it’s an interesting investigation into some of the deeper settings within the slicer. Reducing filament waste and print time is an admirable goal, and if you make your own extruder, you can turn all of that purge waste into various shades of greenish brownish filament.

We’re willing to bet most Hackaday readers have accidentally spot welded a few electrical contacts together over the years, complete with the surge of adrenaline that comes with the unexpected pops and sparks. It’s a mistake you’ll usually only make once or twice. But where most of us would look back at such mishaps as cautionary experiences, [Styropyro] sees an opportunity.

Armed with 100 car batteries wired in parallel, his recent video sees him pitting an assortment of household objects against the combined might of eighty-five thousand amps. Threaded rods, bolts, and angle iron all produce the sort of lightshow you’d expect, but [Styropyro] quickly discovered that holding larger objects down was more difficult than anticipated. It turns out that the magnetic fields being generated by the incredible amount of current rushing through the system was pulling the terminals apart and breaking the connection. After reinforcing the business end of his rig, he was able to tackle stouter objects such as crowbars and wrenches with explosive results.

We found that his remotely operated switch, built out of a hydraulic log splitter, to be a particular highlight of the video — unfortunately he only briefly goes over its construction at the very start. His side experiment, fashioning an sort of manually-operated carbon arc lamp with a pair of thick graphite electrodes and demonstrating is luminous efficacy compared to modern LEDs was an unexpected treat. As was the off-the-shelf domestic circuit breaker that impressed [Styropyro] by refusing to yield even after repeated jolts.

While the showers of sparks and vaporized metal might trigger some sweaty palms among the audience, we’ve seen [Styropyro] handle far scarier contraptions in the past. Though he may come off as devil-may-care in his videos, we figure there’s no way he could have made it this long without blinding or maiming himself if he didn’t know what he was doing.

Another Kickstarter, another opportunity for people to get mad at delayed and poorly functioning (if delivered at all) gadgets. This project aims to make airless tires for bikes and scooters using nitinol, and despite the company’s failed attempt at pedaling their wares on Shark Tank last year, the campaign has already more than quadrupled its funding goal.

The real star of the show here is NiTinol, a shape metal alloy composed of nickel and titanium. We should soon see a real commercial application of this miracle metal, and not long after we’ll see what happens when the rubber meets the road on these airless tires and their long-term performance. It’s not accurate to say they don’t use rubber; they just use LESS, because they’re still treaded, albeit with a layer that is adhered to the metal coil, and you don’t need tubes, either. The tread will still wear down and needs to be replaced occasionally for the lifetime of the tire, but the real advantage is never having a flat tire again. Considering how inconvenient flats are and the number of meetings I’ve been late commuting to because of an unplanned rapid deflation, these tires might be worth it. If you’re wondering why they’re so expensive, some napkin calculations of the nitinol coil have somewhere between 100 ft – 200 ft of wire per wheel, and at $1-2/ft, the raw materials alone before assembly make it an expensive piece of kit.

So what’s so cool about nitinol that it’s worth playing with, and what does it do that spring steel or stainless steel can’t? Well, you can soak it in acid for a year, and it will continue unaffected. It has excellent bio-compatibility, so you can put it in someone’s arteries as a stent, and it will go through tens of millions of cycles without cracking. It’s 10 times better at recovery and lighter, and it’s not magnetic, which can be useful. The memory capability is handy, too, because it means you can rapidly prototype springs, then heat and quench them to set their memory and easily adjust them.

Admittedly, I don’t have a use for it right now. But just like the coils of nichrome and piano wire waiting anxiously in my bins for their opportunity to shine, nitinol is screaming for a fun use.

Growing up in Montana I remember looking out at night and seeing the Milky Way, reminding me of my insignificance in the universe. Now that I live in a city, such introspection is no longer easy, and like 1/2 of humanity that also lives in urban areas, I must rely on satellites to provide the imagery. Yet satellites are part of the problem. Light pollution has been getting worse for decades, and with the recent steady stream of satellite launches and billionaire joyrides we have a relatively new addition to the sources of interference. So how bad is it, and how much worse will it get?

Looking up at the night sky, you can usually tell the difference between various man-made objects. Planes go fairly slowly across the sky, and you can sometimes see them blinking green and red. Meteors are fast and difficult to see. Geostationary satellites don’t appear to move at all because they are orbiting at the same rate as earth’s rotation, while other orbit types will zip by.

SpaceX has committed to reducing satellite brightness, and some observations have confirmed that new models are a full magnitude darker, right at the threshold of naked-eye observation. Unfortunately, it’s only a step in the right direction, and not enough to satisfy astronomers, who aren’t looking up at the night sky with their naked eyes, naturally.

The satellites aren’t giving off the light themselves. They are merely reflecting the light from the sun back to the earth, exactly the same way the moon is. Thus something that is directly in the shadow of the Earth will not reflect any light, but near the horizon the reflection from the satellites can be significant. It’s not practical to only focus our observatories in the narrow area that is the Earth’s shadow during the night, so we must look closer to the horizon and capture the reflections of the satellites.

What Would Satisfy Astronomers?

When photographing the stars, the galactic paparazzi are using complicated and sensitive equipment. The exposure times are very long in order to gather enough light. But when a satellite passes over, its brightness can saturate the CCD, which doesn’t just ruin one pixel in the image, but a whole line as the satellite streaked through the shot. Further, the camera is focused way beyond low earth orbit, so the satellite is blurry, making the thin line into a wide gash across the image. Thus in any given image, the efficiency of the image, or how many pixels are usable, is significantly impacted by any satellite passing overhead.

The relative movement of all of the celestial bodies, and the rotation of Earth and position of the observatory are all calculated by a scheduler that determines when the best time is to take a photo of a specific part of the sky. It’s certainly possible to add the positions of satellites into that calculation to determine when is the optimum time to take a photo without interference. But with thousands of satellites already in space, and tens of thousands more planned, the windows are getting shorter and shorter, the delays until the right time is available are getting longer and longer, and the calculations become not about avoiding images with satellites but just reducing the number of gashes.

Astronomers can calculate the exact loss of efficiency caused by the satellites. At the Rubin Observatory LSST, they have found that with 48000 LEO satellites in orbit, about 30% of all LSST images would contain at least one satellite trail, and at least 1% of pixels would be lost. Further, because multiple images must be taken to compare, and a lot more math has to be applied to pixels to mathematically erase the trails (as long as the pixels hadn’t reached saturation), the extra effort required would extend surveys by several months.

The effects could be catastrophic. When it’s so bright in here that we can’t see out, we can’t identify external threats, like approaching asteroids. We already know where many of the nearby stars are and the mechanics of their motion, but we don’t often know about the much smaller, much dimmer asteroids that may have paths we don’t know about, that could intersect with ours. Being able to detect them requires constant attention to the vastness of our surroundings, and they could easily be masked by a passing satellite, delaying their detection.

So what’s the right amount for astronomers? The idealists might say only theirs. The pragmatic want to work with the space companies to take measures to reduce their impact. And the fearful worry that if efforts aren’t put in from the beginning then it will become a free-for-all with nobody bothering to put in the work to reduce their impact.

What About Us Plebs?

It’s one thing for the individual satellites to be visible to the naked eye, but even if they were darkened, the cumulative effect of tens of thousands of satellites scatters enough light that the night sky becomes brighter overall. With all the objects currently in the sky it’s estimated to be about 10% brighter already than it was in the 70s. If you live in the city and can’t already see the stars, maybe this doesn’t affect you at all. But for everyone else, this may mean the difference between seeing the Milky Way and not. Being able to see it in Montana was profound; for the whole world to be denied that so that some people can get better Internet is disappointing.

[Banner photo: “Castle Geyser & Milky Way”, NPS photo by Neal Herbert, Public Domain]

Most projects around here involve some sort of electronics, and some sort of box to put them in. The same is true of pretty much all commercially available electronic products as well.

Despite that, selecting an enclosure is far from a solved problem. For simple electronics it’s entirely possible to spend more time getting the case just right than working on the circuit itself. But most of the time we need to avoid getting bogged down in what exactly will house our hardware.

The array of options available for your housing is vast, and while many people default to a 3D printer, there are frequently better choices. I’ve been around the block on this issue countless times and wanted to share the options as I see them, and help you decide which is right for you. Let’s talk about enclosures!

Cardboard: Great for Both Enclosures and Proofing PCB Layout

You need something quick and dirty and temporary for a proof of concept or a short-lived project. Why not use some cardboard you have laying around?

Cardboard is easy to work with, and you can rapidly put in holes and slots for your interfaces and connectors. Draw on it, shape it, whatever it takes. Use card stock (like a cereal box) for even higher quality finer dimension work. In the world of rapid prototyping, cardboard is a fantastic option for generating quick iterations that test out usability and rough ideas. It also has a similar thickness to a .062″ PCB, making it quick and easy to print your design, glue it to cardboard, cut it out, and have a temporary substitute to do your mechanical work while you’re waiting for the real ones to arrive by mail.

Plastic Food Containers

When you need a little more sturdiness or water resistance, reusable plastic food enclosures, including yogurt containers and Tic Tac packaging, can go a long way as well. This high-fiving mobile disco turtle robot was made under the direction of a 5-year-old. The yogurt container holds the batteries, speaker, Arduino, and all the wiring, securing the sensitive parts just enough for this limited-lifetime monstrosity.

Find something roughly the size and shape you need, and trim and drill as necessary. A utility blade is the only tool needed to make a higher fidelity enclosure, and careful application of heat or glue can seal and stick parts together. Unless your aim is a kitsch-y product, you shouldn’t expect to do more than a couple of these, and their durability is limited, so expect that this will last only a little bit longer than cardboard, and better for wetter environments.

Clay/Moldable Plastic

If you have skills with molding and can take a block of material and form it to your vision, then clay might be a good option, or oven-bake polymer (Sculpey). InstaMorph is another tool that consists of plastic that softens at low heat and becomes moldable. It’s available in sheets and pellets and can be softened with hot water or air and worked by hand until it cools.

Use Existing Enclosures

This option doesn’t get enough attention. Existing enclosure are perfect for small volumes, and bridge the gap between prototype and high volume production. Polycase, New Age Enclosures, Takachi, Bud, and Hammond are all places that I have used in the past for enclosures that are injection molded, extruded, or otherwise pre-fabricated, and can easily be modified to suit your exact needs (and no, we’re not being paid to mention any of them).

Once you become familiar with their product lines, you’ll start to recognize their enclosures in other products. You pick out an enclosure of the right size and type, and most of them provide CAD of some form (or at least PDF design drawings with relevant dimensions) and usually even suggested PCB outlines. Order one or a few and you have everything you need for only a couple bucks. When it’s time to take it to production, you can even give these companies drawings of any milling that’s needed, or printing on any face, and they’ll take care of that for you, too, for a small setup fee and per part cost.

3D Printed

There’s no shortage of articles about 3D printing here, and it seems like this is a default choice for people even when faster, cheaper, cleaner-looking options exist.

If your needs extend beyond a box, and you must have some kind of special enclosure to fit a specific shape, or you are trying to make it quickly or miniature, then 3D printing may work. You’ll have to bust out the CAD program of your choice, or find an existing design, and this is one of the things that makes this option less accessible to many, and can be very time consuming. On the plus side, a variety of materials are available, there are services that will 3D print and mail you the part, and many public libraries are even getting in on the 3D printer as a service they offer.

Laser Cut

If you have access to it, laser cutting is a decent option as well. Generally these are acrylic or plywood enclosures, though cardboard works well, too, with the edges either interlocking or straight. There are online generators for simple customizable boxes like MakerCase and Boxes.py, and you can modify them after downloading to add your holes and cutouts.

Injection Mold

Injection molds are the industry standard for high volume production, capable of spitting out plastic parts at phenomenal rates and running continuously. They can be designed to exact specifications, and last for anywhere from a few thousand up to millions of parts. The downside is the up-front costs, which can be in the thousands of dollars for basic molds, and millions for really high volume hardened steel with slides and multiple cavities and cooling lines. We’ve covered injection molding in detail, but the primary thing to remember about injection molding is that it’s not for a one-off, and you won’t be able to change your design easily once the tool is cut.

Others: CNC, Casting, and Composite

There are countless other options. You could make your enclosure out of wood or metal in a shop using CNC. There are all kinds of casting techniques, including 3D printing the mold and casting inside the mold, or 3D printing the positive, creating a silicone mold of it, and then casting parts inside the mold. You could put everything in a temporary enclosure and pot it (essentially dump epoxy in to fill it up). You could use a combination of methods to make different parts of your enclosure, or even sub-components. I’ve 3D printed and laser cut brackets for use in an existing enclosure.

Conclusion

Before you jump straight to your CAD software to spend a few hours designing a box and 3D printing it, consider other options that may be faster or cheaper or look better. Of course, this article wasn’t an exhaustive list, but if I missed something significant, mention it below.