Scratch-Built 3D-Printer Goes Back To The Roots Of The Hobby

September 2, 2018 by Dan Maloney 19 Comments

It’s so easy and so cheap to order things like CNC routers and 3D-printers off the shelf that we can be forgiven for forgetting what was once involved in owning machines such as these. It used to be that you had no choice but to build your machine from the ground up. While that’s less true today, it’s still the case if you want to push the limits of what’s commercially available, and this huge scratch-built 3D-printer is a good example of that.

It’s not exactly a fresh build – [Thomas Workshop] posted this last year – but it escaped our notice at the time, and we think the three-part video series below that details the build deserves a look over. When we say scratch built, we mean it. This machine started off as a bundle of aluminum and steel stock. No 80/20 extrusions, no off-the-shelf linear rails – just metal and a plan. The build was helped considerably by a small CNC router, which also had that DIY look, but most of the parts were cut and finished with simple hand tools. The resulting gantry allows an enormous work volume 40 cm in each dimension, with a heated bed that uses four heat mats. We were impressed that [Thomas] got the build just far enough to print parts that were used to finish the build – that’s the hacker spirit.

It’s perhaps not the biggest 3D-printer we’ve seen – that distinction might go to this enormous 8-cubic foot machine – and it certainly can’t print a house. But it’s an impressive build that probably cost a whole lot less than a commercial machine of similar capacity, and it’s got that scratch-built cred.

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Hummingbirds, 3D Printing, And Deep Learning

August 31, 2018 by Ben James 15 Comments

Setting camera traps in your garden to see what local wildlife is around is quite popular. But [Chris Lam] has just one subject in mind: the hummingbird. He devised a custom setup to capture the footage he wanted using some neat tech.

To attract the hummingbirds, [Chris] used an off-the-shelf feeder — no need to re-invent the wheel there. To obtain the closeup footage required, a 4K action cam was used. This was attached to the feeder with a 3D-printed mount that [Chris] designed.

When it came to detecting the presence of a hummingbird in the video, there were various approaches that could have been considered. On the hardware side, PIR and ultrasonic distance sensors are popular for projects of this kind, but [Chris] wanted a pure software solution. The commonly used motion detection libraries for this type of project might have fallen over here, since the whole feeder was swinging in the air on a string, so [Chris] opted for machine learning.

A RESNET architecture was used to run a classification on each frame, to determine if the image contained a hummingbird or not. The initial attempt was not greatly successful, but after cropping the image to a smaller area around the feeder, classification accuracy greatly increased. After a bit of FFmpeg magic, the selected snippets were concatenated to make one video containing all the interesting parts; you can see the result in the clip after the break.

It seems that machine learning and wildlife cams are a match made in heaven. We’ve already written about a proof-of-concept project which identifies different animals in the footage when motion is detected.

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Laser Arm Cannon Scares More Than Metroids

August 30, 2018 by Tom Nardi 5 Comments

There’s an interesting side effect of creating a popular piece of science fiction: if you wait long enough, say 30 or 40 years, there’s a good chance that somebody will manage to knock that pesky “fiction” bit off the end. That’s how we got flip phones that looked like the communicators from Star Trek, and rockets that come in for a landing on a tail of flame. Admittedly it’s a trick that doesn’t always work, but we’re not in the business of betting against sufficiently obsessed nerds either.

Coming in right on schedule 32 years after the release of Metroid on the Nintendo Entertainment System, we now have a functional laser arm cannon as used by the game’s protagonist Samus Aran, courtesy of [Hyper_Ion]. It’s not quite as capable as its video game counterpart, but if your particular corner of the solar system is under assault from black balloons you should be in good shape. Incidentally no word yet on a DIY Power Suit that folds the wearer up into a tiny ball, but no rush on that one.

Modeled after the version of the weapon Samus carried in 2002’s iconic Metroid Prime, [Hyper_Ion] 3D printed the cannon in a number of pieces that screw together in order to achieve the impressive final dimensions. He printed it at 0.3 mm layers to speed up the process, but as you can probably imagine, printing life-size designs like this is not for the faint of heart or short of time. While the use of printed threads does make the design a bit more complex, the fact that the cannon isn’t glued together and can be broken down for maintenance or storage is a huge advantage.

Ever popular NeoPixel strips give the cannon a bit of flash, and a speaker driven by a 2N2222 transistor on an Arduino Nano’s digital pin allows for some rudimentary sound effects with nothing more than a PWM signal. In the video after the break you can see how the lights and sounds serve as a warning system for the laser itself, as the cannon can be seen “charging up” for a few seconds before emitting a beam.

Of course, this is the part of the project that might have some readers recoiling in horror. To provide some real-world punch, [Hyper_Ion] has equipped his arm cannon with a 2.5W 450nm laser module intended for desktop engraving machines. To say this thing is dangerous is probably an understatement, so we wouldn’t blame you if you decided to leave the laser module off your own version. But it certainly looks cool, and as long as you’ve got some proper eye protection there’s (probably) more dangerous things you can do in the privacy of your own home.

Shame this kind of technology wasn’t really practical back when [Ryan Fitzpatrick] made this fantastic Power Suit helmet for a Metroid fan production.

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3D Printed Magnetic Dust Port Keeps Shop Clean

August 29, 2018 by Tom Nardi 33 Comments

Too often we hear that 3D printing is at best only a way for making prototypes before you invest in “real” manufacturing. At worst, it’s a way to make little toys for your desk or cubicle. The detractors say that 3D printing doesn’t lend itself to building practical devices, and even if you do manage to print something useful, you probably could have made it faster or better with more traditional manufacturing methods. So naturally we’re especially excited when we see a printed design that manages to buck both criticisms at once.

Not only does this magnetic dust port connector created by [Taylor Landry] have a clear practical purpose, but its design largely defies normal construction techniques. It consists of two flanges, sized for common 4″ flexible ducting, which feature embedded magnets on the faces.

This allows the two sides of the coupling to easily be connected and disconnected without relying on threads or a friction fit. Not only would threads likely get caked with sawdust, but the magnetic connection allows the coupling to release in the event somebody trips on the duct or the tool is moved.

Currently only one type of coupling is available, but [Taylor] says he’s looking at adapting the design to other tools. He also mentions that the magnets he’s currently using are a custom size he had left over from a previous project, so if you’re looking to replicate the design you might need to tweak the magnet openings. Luckily, he’s provided the STEP files so you don’t have to hack the STL.

A quick connect dust port like the one [Taylor] has come up with seems like it would be a perfect addition to the whole-shop dust collection systems we’ve covered in the past. In fact, it might not even be the only 3D printed component in the system.

Empty Can Upcycled Into Portable Speaker

August 28, 2018 by Tom Nardi 26 Comments

We aren’t suggesting you go digging through the trash looking for empty cans, but if you’ve already got some empty cans in the privacy of your own home, you could certainly do worse than turning them into unique enclosures for your electronics projects. Better than sitting in the landfill, surely.

This hack from [Robin Hartley] turns an empty Cadbury hot chocolate can into a portable speaker that’s sure to get some attention. But don’t be fooled: a surprisingly amount of engineering went into this project in the form of a 3D printed structure on the inside of the can. Even if you aren’t big on the idea of putting your next project into a piece of literal trash, there’s something to be said for how professionally everything fits together in this build.

The key to this build is the 3D printed “skeleton” that holds the speaker and circuit board in place. An especially nice touch is how [Robin] designed the mount for the speaker: as it had no flange to attach to, he made a two piece clamp that screws together around the rear of the speaker and holds it in place.

You may wonder why somebody who’s clearly as well versed in CAD and 3D printing as [Robin] is might want to use an empty can as an enclosure; surely he could just design and print a case? Undoubtedly. But the goal here is to reuse what would otherwise be trash, and that occasionally means taking the “scenic” route as it were.

To take this concept to the next level, check out the upcycled speaker box we recently covered. We’ve seen some gorgeous home audio builds that started as a curbside find, but depending on how lucky you are, it’s almost like cheating.

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OpenSCAD Handles The Math In 3D Printed Holder For Magnetic Spheres

August 28, 2018 by Donald Papp 35 Comments

3D printed holder mounted to bike wheel, fitting precisely 38 magnetic spheres around its perimeter. Tedious math? Not if you make OpenSCAD do it.

Off-the-shelf components are great; the world and our work simply wouldn’t be the same without. But one of the constraints is that one has to design around them, and that’s what led [Antonio Ospite] to create a parametric design in OpenSCAD for a 3D printed holder which snugly fits a number of magnetic spheres around its diameter.

If that sounds a bit esoteric, it will become much clearer in the context of [Antonio]’s earlier work in making a DIY rotary encoder out of a ring of magnetic spheres. He found that such a ring in front of two Hall effect sensors was low in cost, high in precision, and thanks to 3D printing it also had a lot of potential for customizing. But hampering easy design changes was the need for the spheres to fit snugly around whatever shape was chosen for the hardware, which meant constraints on the encoder diameter.

In this case, [Antonio] wished to create an encoder that could be attached to a bicycle wheel but needed to know what outer diameter would best fit a ring of magnetic balls perfectly, given that the balls were each 5 mm. OpenSCAD did the trick, yielding a design that fit the bike wheel and spokes while perfectly nestling 38 magnetic balls around the outside edge with a minimum of wasted space.

OpenSCAD is a CAD program that’s really more like a programming language than anything else. For those who are not familiar with it, [Brian Benchoff] walked through how to make a simple object in OpenSCAD, and [Elliot] has sung the praises of a few advanced functions. Now that this project makes DIY encoders easier, perhaps they could be used to add intuitive new controls to OpenSCAD itself.

PiPod: A Raspberry Pi Zero Portable Music Player

August 28, 2018 by Ben James 16 Comments

[Bram] wasn’t satisfied with the portable music playback devices that were currently available. He craved an offline music player that had a large storage capacity but found that this was only available in high-end, off-the-shelf options, which were far too expensive. [Bram] decided to make his own, powered by a Raspberry Pi zero. After building an initial prototype, the design was iterated a few times, with the latest version featuring a BOM cost of roughly €80.

The whole project is open source, with hardware and software files available on the project GitHub. A 2.2″ TFT displays the UI, which is of course completely customisable. Everything is squashed into a 3D printed case, which has the smallest form factor possible whilst retaining a decent amount of battery life. The electronics are what you’d expect: a boost converter to produce 5 V for the Pi from the 3.7V battery, a charge controller and a battery protection circuit. As a bonus, the battery voltage is monitored with a 12-bit ADC which reports to the Pi, enabling it to do a safe shutdown at low voltage, and display battery level on the UI.

Since the whole purpose of the device is to play audio, onboard filtered PWM wasn’t going to cut it, so instead a 24-bit DAC talks to the Pi via I2S. The audio player backend is VLC, so there’s support for plenty of different file types. A disc image of the whole system is available with everything pre-configured, and you can even buy the assembled PCB from Tindie.

Want to keep the look and feel of your old iPod? We covered an impressive restoration of a 6th gen model, upgrading the storage and battery significantly.