3D Printing Snap Fit Joints

March 14, 2022 by 10 Comments

Owning a 3D printer seems to progress through stages. You start printing simple shapes. Then you get serious about calibration and quality. Eventually, you move to trying to design and build practical things. To get practical, you often need to join parts together and that requires glue, fasteners, threaded inserts, and plastic welding. However, you can also make parts that fit together using friction and the springiness of plastic. For example, [Lucas Carolo] recently had a look at 3D printing snap-fit joints. These are commonly seen on the end of straps so that you can connect two ends together.

Of course, you can use them anywhere you need a secure connection. However, you might want to consider that since the jaws compress, there will be repeated stress on the part, so it might not be a good choice for items that you will frequently snap together. Also, brittle plastic such as PLA might not be the best choice of materials. There are several different kinds of joints. The cantilever version has a hook that bends into place and, as mentioned earlier, is common on luggage or backpack straps. The post offers tips on how to design a durable hook. In particular, the orientation of the hook during printing is critical because of the stress involved.

Another type of snap-fit joint is the kind you find on many snap electronic enclosures or things like pen caps. In these joints, a large bump (a boss) fits into a similar groove on the other part. The post has a little less information on these but does mention that you should form the bosses with a chamfer. If you want more details, the post links to a great guide and an enclosure tutorial that you should check out.

We’ve covered this topic before and have some other guides to check out. We’ve also seen some pretty innovative connecting methods.

Beautiful Engineering In This Laser Unit From A Tornado Jet Fighter

March 13, 2022 by 18 Comments

Those of use hailing from the UK may be quite familiar with the Royal Air Force’s Tornado fighter jet, which was designed to fight in a theoretical nuclear war, and served the country for over 40 years. This flying deathtrap (words of an actual serving RAF fighter pilot this scribe met a few years ago) was an extremely complex machine, with state-of-the-art tech for its era, but did apparently have a bit of a habit for bursting into flames occasionally when in the air!

Anyway, the last fleet is now long retired and some of the tech inside it is starting to filter down into the public domain, as some parts can be bought on eBay of all places. [Mike] of mikeselectricstuff has been digging around inside the Tornado’s laser head unit,  which was part of the bomber’s laser-guided missile subsystem, and boy what a journey of mechanics and electronics this is!

Pulse-mode optically pumped YAG laser

This unit is largely dumb, with all the clever stuff happening deep in an avionics bay, but there is still plenty of older high-end tech on display. Using a xenon-discharge-tube pumped yttrium aluminum garnet (YAG) laser, operating in pulsed mode, the job of the unit is to illuminate the ground target with an IR spot, which the subsequently fired missiles will home on to.

Designed for ground-tracking, whilst the aircraft is operating at speed, the laser head has three degrees of moment, which likely is synchronized with the aircraft movement to keep the beam steady. The optical package is quite interesting, with the xenon tube and YAG rod swimming in a liquid cooling bath, inside a metal housing. The beam is bounced around inside the housing using many prisms, and gated with a Q-switch which allows the beam to build up in intensity, before be unleashed on the target. Also of note is the biggest photodiode we’ve ever seen — easily over an inch in diameter, split into four quadrants, enabling the sensor to resolve direction changes in the reflected IR spot and track its error. A separate photodiode receiver forms part of the time-of-flight optical range finder, which is also important information to have when targeting.

There are plenty of unusual 3-phase positioning motors, position sensors, and rate gyros in the mix, with the whole thing beautifully crafted and wired-up military spec. It is definitely an eye opener for what really was possible during the cold war years, even if such tech never quite filtered down to civilian applications.

We’ve seen a few bits about the Tornado before, like this over-engineered attitude indicator, and here’s the insides of an old aircraft QAR (Quick Access Recorder)

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Reversible Ventilation Hack Keeps The Landlord Happy

March 13, 2022 by 26 Comments

When a person owns the home they live in, often the only approval they need for modifications is from their significant other or roommate. In the worst case, maybe a permit is required. But those who rent their dwellings are far more constrained in almost every case, and when it comes to environmental controls, they are most decidedly off limits. Unless you’re a resourceful hacker like [Nik], that is, who has seamlessly integrated his apartment’s ventilation system into his smart home controller — all without any permanent modifications!

The controller itself only gives three settings to vent the apartment: Low, Medium, High, and then High for 30 minutes, with all modes having to be actuated with a manual button press. [Nik] wanted automation and integration with his smart home.

A clean 3D printed enclosure wraps things nicely

Thankfully, the engineers who designed the controller used in [Nik]’s apartment made it very convenient to reverse engineer it. A flat ribbon cable conveniently breaks out all of the buttons and 12 VDC, and he can interface directly using its connector. First hack: done.

Next, [Nik] needed a longer cable to run between the controller and his ESP8266 based control module. Finding the connector on AliExpress was easy, but finding a compatible cable of length required some more resourcefulness. The cable was eventually sourced from the airbag controller of a Renault Megane! Second hack, using a car part in a controller: well done!

Integration into his smart home wasn’t just electronic. The module looks right at home above the original controller, and if you didn’t know better you’d never think it wasn’t original equipment. Final hack: Done!

Be sure to check out his build log over at Hackaday.io, and if home automation hacks are your cup of tea, check out this automatic tea maker.

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Hackaday Links: March 13, 2022

March 13, 2022 by 13 Comments

As Russia’s war on Ukraine drags on, its knock-on effects are being felt far beyond the eastern Europe theater. And perhaps nowhere is this more acutely felt than in the space launch industry, seeing that at least until recently, Russia was pretty much everyone’s go-to ride to orbit. All that has changed now, at least temporarily, and has expanded to include halting sales of rocket engines used in other nations’ launch vehicles. Specifically, Roscosmos has put an end to exports of the RD-180 engine used in the US Atlas V launch vehicle, along with the RD-181 thrusters found in the Antares rocket. The loss of these engines may be more symbolic than practical, at least for the RD-180 — United Launch Alliance stopped selling launches on Atlas V back last year, and had secured the engines it needed for the 29 flights it has booked by that April. Still, there’s some irony that the Atlas V, which started life as an ICBM aimed at the USSR in the 1950s, has lost its Russian-made engines.

Bad news for Jan Mrázek’s popular open-source parametric search utility which made JLCPCB’s component library easier to use. We wrote about it back in 2020, and things seemed to be going fine up until this week, when Jan got a take-down request for his service. When we first heard about this, we checked the application’s web page, which bore a big red banner that included what were apparently unpleasant accusations Jan had received, including the words “reptile” and “parasitic.” The banner is still there, but the text has changed to a more hopeful tone, noting that LCSC, the component supplier for JLC’s assembly service, objected to the way Jan was pulling component data, and that they are now working together on something that everyone can be happy with. Here’s hoping that the service is back in action again soon.

Good news, everyone: Epson is getting into the 3D printer business. Eager to add a dimension to the planar printing world they’ve mostly worked in, they’ve announced that they’ll be launching a direct-extrusion printer sometime soon. Aimed at the industrial market, the printer will use a “flat screw extruder,” which is supposed to be similar to what the company uses on its injection molding machines. We sure didn’t know Epson was in the injection molding market, so it’ll be interesting to see if expertise there results in innovation in 3D printing, especially if it trickles down to the consumer printing market. Just as long as they don’t try to DRM the pellets, of course.

You can’t judge a book by its cover, but it turns out that there’s a lot you can tell about a person’s genetics just by looking at their face. At least that’s according to an AI startup called FDNA, which makes an app called “Face2Gene” that the company claims can identify 300 genetic disorders by analyzing photos of someone’s face. Some genetic disorders, like Down Syndrome, leave easily recognizable facial features, but some changes are far more subtle and hard to recognize. We had heard of cases where photos of toddlers posted on social media were used to diagnose retinoblastoma, a rare cancer of the retina. But this is on another level entirely.

And finally, working in an Amazon warehouse has got to be a tough gig, and if some of the stories are to be believed, it borders on being a horror show. But one Amazonian recently shared a video that showed what it’s like to get trapped by his robotic coworkers. The warehouse employee somehow managed to get stuck in a maze created by Amazon’s pods, which are stacks of shelves that hold merchandise and are moved around the warehouse floor by what amounts to robotic pallet jacks. Apparently, the robots know enough to not collide with their meat-based colleagues, but not enough to not box them in. To be fair, the human eventually found a way out, but it was a long search and it seems like another pod could have moved into position to block the exit at any time. You could see it as a scary example of human-robot interaction gone awry, but we prefer to look at it as the robots giving their friend a little unscheduled break away from the prying eyes of his supervisor.

Mini PC with the mod described, a large tower fan sticking out of a hole in the top cover

MiniPC Surgery Makes It 50% Cooler

March 13, 2022 by 27 Comments

[G3R] writes to us about a mod they did on a HP ProDesk/EliteDesk 400 G3 miniPC they use as a home emulation center. The miniPC would overheat as soon as the CPU load increased, resulting in frame drops and stutters, as well as throttling CPU. [G3R] took the original cooling solution, threw out half of it and modified the remaining half to accept a tower CPU cooler.

The modification is invasive in all the right ways. [G3R] shows how to de-fin the current heatsink and smooth it over with a… welder? Our guess is that the heatsink fins were soldered to the heatsink base, and in that case, a heat gun should also work. Afterwards, you’re supposed to cut a hole in the upper case, then re-wire the fan connections, and create custom brackets to attach the tower fan – [G3R] explains how to do it all and what to watch out for.

The results are fascinating. After performing the mod, both idle and under-load temps got cut down by 50%! Idle temps went from 50 to 25 °C, and under-load temps dropped from 79 to 40 °C – surely, with way less throttling involved. Not only this lets [G3R] play Breath Of The Wild without hiccups, it also certainly improves overall lifespan of the mini-PC, despite the intervention being mechanically harsh.

Making our devices, quite literally, cooler is a venerable tradition of hackers. Just a few weeks ago, we covered a simple 3D printable LGA 1700 CPU bracket which can gain you some much-desired thermal contact. Sometimes we encounter proprietary and weird cooling fans that fail, and then we understand their workings and build a substitute. And, even if your GPU was never meant to have a fan, you can add one anyway!

5-Axis 3D Printing For The Rest Of Us

March 13, 2022 by 29 Comments

By now we’re all used to the idea of three dimensional printing, as over the last fifteen years or so it’s become an indispensable tool for anyone with an interest in making things without an industrial scale budget. There are still a few limitations to the techniques used in a common 3D printer though, in particular being tied to layers in a single orientation. It’s something that can be addressed by adding tilt and rotational axes to the printer to deliver a five-axis device, but this has not been available in an affordable form. [Freddie Hong] and colleagues have tackled the production of an affordable printer, and his solution fits neatly on the bed of a Prusa i3 to convert it to five-axis machine without breaking the bank.

The quantity and quality of the work is certainly impressive, with suitable slicing software being developed alongside the 3D printed parts to fit the two extra axes. For now all we can do is look at the pictures and the video below the break, but once the work has been presented the promise that all the necessary files will be made public. We can see versions of the hardware finding their way onto printers other  than the Prusa, and we can see this becoming yet another piece of the regular armory available to those of us who make things.

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Haptic Smart Knob Does Several Jobs

March 13, 2022 by 63 Comments

A knob is a knob, a switch is a switch, and that’s that, right? And what about those knobs that have detents, set in stone at the time of manufacturing? Oh, and those knobs that let you jog left to right and then snap back to center — that can’t be modified…right? Well, you likely know where this is going, and in the video below the break, [scottbez1] shows off a new open source haptic input knob that can be all of these things with just some configuration changes!

The list of possibilities is long: virtual snap points, virtual spring loading, virtual detents, virtual end points. It’s a virtual smörgåsbord of configuration options that make this haptic smart knob a one stop shop for all of your knob needs. This is all possible because the knob contains a high resolution magnetic encoder chip that has a single degree resolution. The sensor is coupled, through software, to a brushless DC motor. The round LCD gives visual feedback as well.

As [Myself] on the Hackaday Discord channel noted, having configurable spacing and strength for detents, springs, and stops, is nothing short of incredible. Being able to reconfigure the knob at-will means that it can become context sensitive. It’s wonderfully unique and it’s open source, so you can make your own with the information available at GitHub.

And according to its creator, the only thing the Haptic Smart Knob can’t do is do your taxes or blend your margarita. Well, it’s open source, so perhaps some of our more enterprising readers can submit just the right pull request.

This isn’t Hackaday’s first Motorized Volume Knob feature, but it might be one of the neatest we have seen so far. Thanks to [mattvenn] on the Hackaday Discord server for the great tip!

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