Gramazon Gives Your Echo Dot A 1920’s Makeover

March 11, 2018 by Tom Nardi 23 Comments

Unless you’re particularly fond of hockey pucks, you probably aren’t really keen on the aesthetics of ~~the NSA’s~~ Amazon’s diminutive listening device, the Echo Dot. It’s not exactly ugly, but if anyone at Amazon spent more than ten minutes considering the visual design of the thing when it was being developed, we’d be shocked.

Luckily for us, there are hackers and makers who not only have the artistic chops to come up with visually appealing designs, but are kind enough to share them with those of us who are a few crayons short of a full box in that department. Such is the case with the jaw-dropping Gramazon by [Bård Fleistad], a 3D printed acoustic amplifier for the Echo Dot that converts the ho-hum looking device into a classic 1920’s style “horn” speaker.

[Bård] has wanted a horn speaker for awhile, but the prices on a real one in decent condition are getting pretty high. If he couldn’t have the real deal he figured the next best thing would be to 3D print his own version, but he’d still need electronics to put into it. Since the Echo is readily available and works as a Bluetooth speaker (not to mention plays audio from various online sources), it made sense to use it as the heart of his faux-horn.

The design he came up with is very slick, but the finish work on the printed parts is really what puts this project over the edge. [Bård] used Bondo and multiple primer coats to smooth the outside of the horn, and XTC-3D for the hard-to-reach internal curves. Plus sanding. Lots, and lots, of sanding.

If you’re looking for more information on putting high quality finishes on your 3D printed parts like this, check out our Visual 3D Print Finishing Guide. Or if you’d rather just find a swanky home for your always-listening hockey puck, we’ve got plenty of inspiration for you there as well.

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Single Motor, Single Piece 3D Printed Hovercraft

March 8, 2018 by Steven Dufresne 12 Comments

RC hovercrafts offer all sorts of design options which make them interesting projects to explore. There are dual-motor ones where one motor provides lift while the other does the thrust. For steering, the thrust motor can swivel or you can place a rudder behind it. And there are single-motor ones where one motor does all the work. In that case, the airflow from the motor blades has to be redirected to under the hovercraft somehow, while also being vectored out the back and steered.

[Tom Stanton] decided to make a single-motor hovercraft using only a single 3D printed piece for the main structure. His goals were to keep it as simple as possible, lightweight, and inexpensive. Some of the air from the blades is directed via ducting printed into the structure to the underside while the remainder flows backward past a steering rudder. He even managed to share a bolt between the rudder’s servo and the motor mount. Another goal was to need no support structure for the printing, though he did get some stringing which he cleaned up easily by blasting them with a heat gun.

From initial testing, he found that it didn’t steer well. He suspected the rudder wasn’t redirecting the air to enough of a sideways angle. The solution he came up with was pretty ingenious, switching to a wedge-shaped rudder. In the video below he gives a the side-by-side comparison of the two rudders which shows a huge difference in the angle at which the air should be redirected, and further testing proved that it now steered great.

Another issue he attacks in the video below was a tendency for the hovercraft to dip to one side. He solves this with some iterative changes to the skirt, but we’ll leave it to you to watch the video for the details. The ease of assembly and the figure-eight drift course he demonstrates at the end shows that he succeeded wonderfully with his design goals.

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3D Printering: Print Smoothing Tests With UV Resin

March 8, 2018 by Donald Papp 16 Comments

Smoothing the layer lines out of filament-based 3D prints is a common desire, and there are various methods for doing it. Besides good old sanding, another method is to apply a liquid coating of some kind that fills in irregularities and creates a smooth surface. There’s even a product specifically for this purpose: XTC-3D by Smooth-on. However, I happened to have access to the syrup-thick UV resin from an SLA printer and it occurred to me to see whether I could smooth a 3D print by brushing the resin on, then curing it. I didn’t see any reason it shouldn’t work, and it might even bring its own advantages. Filament printers and resin-based printers don’t normally have anything to do with one another, but since I had access to both I decided to cross the streams a little.

The UV-curable resin I tested is Clear Standard resin from a Formlabs printer. Other UV resins should work similarly from what I understand, but I haven’t tested them.

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Customizing STLs For Off-Brand Devices

March 7, 2018 by Tom Nardi 22 Comments

[Rob Clarke] needed a mount for his off-brand action camera, but it’s not exactly the kind of thing with a bustling accessory market. To make matters worse, it turns out the camera is so low-key that he couldn’t find a 3D printable mount for it either. Luckily, a check with his calipers confirmed his camera is just about the same size as an old GoPro Hero 3, so all he had to do was modify an existing design to fit his needs.

As anyone who’s worked with STL files will tell you, they are a pain to modify. An STL is essentially a completed solid model, and not really meant to be fiddled around with. It’s a bit like trying to take an edited image and get back to the layers that were used to create it in Photoshop or GIMP. The final output has been “flattened”, so that granular control is lost.

That being said, [Rob] got rather lucky in this case. He found a GoPro mount that was about 90% there, he just needed to adjust the depth and change the positioning of the holes on the side. He loaded the STL into SketchUp, deleted the two sides, and replaced them with new surfaces. This gave him a clean slate to add the appropriate openings for his camera’s USB port and microSD card. To adjust the depth of the mount, he simply stretched the model out on the Z axis.

[Rob] event went ahead and released his modified STLs as a remix of the original case he found on Thingiverse for anyone else that has the same camera. That’s what we love to see.

If you’re interested in learning more about using SketchUp for designing 3D printed parts, check out this excellent guide by our very own [Brian Benchoff].

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Lamp’s Ghostly Glow Benefits From Happy Mistake

February 27, 2018 by Donald Papp 8 Comments

[cyborgworkshop]’s youngest sister is a fan of a character in a popular video game (Thresh from League of Legends) who wields an iconic lantern with a mystical green glow. He resolved to make a replica of that lantern. Perhaps as a gift for the cherished family member? Certainly not! [cyborgworkshop]’s goal was the simple joy of having something “to lord over her.” Ah, ain’t siblings grand?

Why the glow powder turned pink in clear varnish is a bit of a mystery.

There were some interesting things learned in the process of making the ghostly green lamp. The first part of the build log is all about post-processing the lantern model, which was 3D printed at a chunky 0.48 mm layer height, but the rest is about getting the ghostly green glow to come out the way it did. [cyborgworkshop] used both glow in the dark paint and glow in the dark powder to really make the object pop, but the process involved some trial and error. Originally he mixed the glow powder into some clear varnish, and despite the mixture turning pink for some mysterious reason, a small sample spot appeared to turn out fine. However, after applying to the lantern and waiting, the varnish remained goopy and the glow powder settled out of the mixture. He ended up having to remove it as best he could and tried a heavy application of the glow paint instead. This ended up being a real blessing in disguise, because the combination resulted in a gritty stone-like texture that glowed brightly! As [cyborgworkshop] observes, sometimes mistakes end up being the highlight of a piece.

After more glow powder for highlighting, the finishing touches were a thin black wash to mute the powder’s whiteness, and a clear coat. The result looks great and a short video is embedded below. Oh, and if anyone has an idea why glow powder would turn pink when mixed into varnish, let us know in the comments!

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This 3D-Printed Robotic Vacuum Sucks

February 24, 2018 by Tom Nardi 11 Comments

After you’ve taken a moment to ponder the turn of phrase used in the title, take a look at this scratch-built robotic vacuum created by [theking3737]. The entire body of the vacuum was 3D printed, and all of the internal electronics are off-the-shelf modular components. We can’t say how well it stacks up against the commercial equivalents from iRobot and the like, but it doesn’t look like it would be too hard to build one yourself to find out.

The body of this rather concerned-looking robot was printed on a DMS DP5 printer, which is a neat trick as it only has a build platform of 200 mm x 200 mm. Once all the pieces were printed, a 3D pen was used to “weld” the sections together. The final result looks a bit rough, but should give a bond that’s just as strong as the printed parts themselves.

The robot has four sets of ultrasonic range finders to detect walls and obstacles, though probably not in the positions you would expect. The right side of the robot has two sets of sensors, while the left side only gets one. We aren’t sure the reasoning behind the asymmetrical layout, but presumably the machine prefers making right turns.

Control is provided by an Arduino Mega and the ever-reliable HC-05 Bluetooth module. A companion Android application was written which allows configuring the robot without having to plug into the Arduino every time you want to tweak a setting.

We can’t say we’ve seen that many DIY robotic vacuums here at Hackaday, but we’ve certainly featured our fair share of hacks for the commercially available models.

Fully 3D Printed Nerf Thirst Zapper

February 24, 2018 by Tom Nardi 6 Comments

In case you weren’t aware, there is a whole community out there that revolves around customizing NERF guns. In that community is a subculture that builds their own NERF guns, and within that group is a sub-subculture that 3D prints NERF guns. So next time you are contemplating how esoteric your little corner of the hacking world is, keep that in mind.

Anyway, [Wekster] is currently making his way in the world of 3D printed one-off NERF guns, and has unveiled his latest creation: a fully 3D printed “Thirst Zapper” from Fallout 4. Except for the springs, each and every piece of this gun was printed on his CR-10 printer. You could even wind your own springs if you really wanted to, and keep the whole thing in-house. Because if you’re going to do something this niche, you might as well go all in.

Even if you aren’t a member of the NERF-elite, the video [Wekster] has put together for this project is a fantastic look at what it takes to design, print, and finish a custom build. From creating the model to mixing the paint to match the in-game model, this video has a little something for everyone.

This isn’t the first time we’ve covered 3D printed NERF guns, but it’s surely the most ornate we’ve ever seen. Interestingly, the bar is set pretty high for Fallout-themed builds in general, so perhaps there’s some unwritten rule out there in regards to Fallout prop builds.

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