For Better Photogrammetry, Just Add A Donut

May 14, 2019 by Kristina Panos 19 Comments

If you don’t have access to a 3D scanner, you can get a lot done with photogrammetry. Basically, you take a bunch of pictures of an object from different angles, and then stitch them together with software to create a 3D model. For best results, you need consistent, diffuse lighting, an unchanging background, and a steady camera.

Industrial designer [Eric Strebel] recently made an Intro to Photogrammetry video wherein he circled an object taking photos with his bare hands. One commenter suggested a different method: build a donut-shaped turntable that circles the object, which sits on a stationary platform. Attach the camera to the donut, counterbalance the weight, and Bob’s your proverbial uncle. [Eric] thought it was a brilliant idea (because it is), and he built a proof of concept. This is that video.

[Eric] can move the camera up and down the arc of the boom to get all the Z-positions he wants. The platform has a mark every 10° and there’s a pointer in the platform to line them up against for consistent camera positioning. He was pleasantly surprised by the results, which we agree are outstanding.

We always learn a lot from [Eric]’s videos, and this one’s no exception. Case in point: he makes a cardboard mock-up by laying out the pieces, and uses that to make a pattern for the recycled plywood and melamine version. In the photogrammetry video, he covers spray paint techniques to make objects reflect as little light as possible so the details don’t get lost.

If you prefer to rotate your objects, get an Arduino out and automate the spin.

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Custom Storage Boxes, From Cardboard And 3D Printed Bits

May 13, 2019 by Donald Papp 14 Comments

It’s not that storage boxes and organizers are hard to find. No, the problem this project set out to solve was more nuanced than that. The real trouble [theguymasamato] had was that his storage options — wide shelves and deep drawers — weren’t well suited to storing a lot of small and light objects. The result was a lot of wasted space and poor organization. To make matters worse, his big drawers had oddball dimensions, meaning that store bought organizers weren’t a good fit either.

To solve these problems, [theguymasamato] decided to design his own stackable boxes to store small and light objects far more efficiently than before. The design also allows the boxes to be made in a variety of sizes without changing any of the 3D printed parts. Carefully measured and cut cardboard is critical, but that’s nothing a utility knife and ruler can’t solve. The only other requirements are a few simple plastic parts, and some glue. He can fit six of these inside a single one of his drawers with enough room to access and handle them, but without wasting space.

Cardboard is really versatile stuff. Not only has it been behind some amazingly complex devices such as this tiny working plotter, but we’ve seen it form major components in the remarkably ambitious cardboard CNC.

3D-Printed Mobius Strip Of Gears

May 11, 2019 by Lewin Day 12 Comments

Exploring the mathematics behind everyone’s favourite unorientable single-sided surface can be quite the mind-bending exercise, so it’s nice that it’s so easy to make a Mobius strip out of paper and a single piece of tape. That demonstration was far from enough for [elmins]. who printed this Mobius strip of gears. The teeth fit together, and all the gears move, but there is still only one side and one edge (we think).

This animation helped spawn the project.

The idea to tackle the project came from seeing an animation of Mobius gears. Wondering if it would be possible to actually create such a thing, [elmins] got to work. The design is printed in 60 pieces, 30 each for the inner and outer parts. The entire assembly is printed in PETG, an unconventional choice but by no means unsuitable. 285 ball bearings help the rings rotate.

The gears use a standard involute bevel profile, though [elmins] suspects this could be an area of further optimisation. The parts were printed in an orientation to ensure the print lines run around the races, allowing for minimal finishing and smooth rolling of the bearings. This is a good study of just what can be achieved with some smart modelling and perseverance.

If you’re thirsty for more madcap machining, consider exploring the concept of the Reuleaux triangle bearing.

Improving A Conference Badge With 3D Printing

May 10, 2019 by Tom Nardi 2 Comments

The obsession with over-the-top-hardware conference badges means that we as attendees get to enjoy a stream of weird and wonderful electronic gadgets. But for the folks putting these conferences on, getting a badge designed and manufactured in time for the event can be a stressful and expensive undertaking. To keep things on track, the designs will often cut corners and take liberties that you’d never see in commercial products. But of course, that’s part of their charm.

As a case in point, the OLED display on the 2019 KiCon badge is held on with just four soldered header pins, and can easily be bent or even snapped off. So [Jose Ignacio Romero] took it upon himself to develop a 3D printable mount which integrates with the PCB and gives the display some mechanical support. Any KiCon attendees who are looking to keep their badge in peak fighting condition for the long haul might want to start warming their extruders.

The design of this upgrade was made all the easier thanks to the fact that the KiCon badge is (naturally) open hardware. That meant [Jose] could import the PCB files directly into FreeCAD and have a virtual model of the badge to work with. This let him check the clearances and position of components without having to break out the calipers and measure the real thing.

Playing around with the virtual assembly, [Jose] quickly realized that the mounting holes in the OLED display don’t actually line up with the holes in the PCB; potentially why the screen didn’t get mounted on the final hardware. Once this misalignment was characterized, he was able to factor it into his design: the PCB side gets screwed down, and the screen snaps into printed “nubs” on the top of the mount.

Hackaday Editor-in-Chief [Mike Szczys] was on hand for KiCon 2019, and was kind enough to share the experience with those of us who couldn’t make it in person, including his own bout of hacking this very same badge.

A 32-bit Boost For Your 3D Printer

May 10, 2019 by Tom Nardi 52 Comments

It might not be the kind of thing you’ve given much thought to, but if you’ve ever used a desktop 3D printer, it was almost certainly being controlled by an 8-bit CPU. In fact, the common RAMPS controller is essentially just a motor driver shield for the Arduino Mega. Surely we can do a bit better than that in 2019?

For his entry into this year’s Hackaday Prize, [Robert] is working on a 32-bit drop-in replacement board which would allow 3D printer owners to easily upgrade the “brain” of their machines. Of course, there are already a few 32-bit control boards available on the market, but these are almost exclusively high-end boards which can be tricky to retrofit into an older machine. It should also go without saying that they aren’t cheap.

With this board, [Robert] is hoping to create a simpler upgrade path for 8-bit printer owners. Being small and cheap is already a pretty big deal, but perhaps equally importantly, his board is running the open source Marlin firmware. Marlin powers the majority of 8-bit desktop 3D printers (even if their owners don’t necessarily realize it) so sticking with it means that users shouldn’t have to change their software configuration or workflow just because they’ve upgraded their controller.

The board is powered by a 72 MHz STM32F103 chip, and uses state-of-the-art Trinamic TMC2208 stepper drivers to achieve near silent operation. The board has an automatic cooling fan to help keep itself cool, and with an XT60 connector for power, it should even be relatively easy to take your printer on the go with suitably beefy RC batteries.

It’s Never Too Early To Prepare For Halloween: With Flamethrowers

May 10, 2019 by Bryan Cockfield 3 Comments

Using a legitimate flamethrower is on the bucket list for a lot of us. Even Elon Musk got into the action with his Not-A-Flamethrower flamethrower. For the rest of us non-billionaires though, we have to come up with clever reasons to build our own like “Halloween is only six months away”. [HandsomeRyan] took this approach six months ago to great effect, and recently released the files on Thingiverse for us all to enjoy.

The cover for building this project was making a Jack-o-Lantern shoot flames out of its face on-demand. The build is based around a car door locking solenoid, which has plenty of kick for applications like this. [HandsomeRyan] upgraded his old wood design with fancy 3D-printed parts which, with the help of the solenoid, deliver a blast of flammable material across a candle inside the Jack-o-Lantern via an aerosol can hidden in the pumpkin.

Part of the elegance of this project is that a car door locking solenoid is typically controlled by remote, meaning that if you want this to be remote-controlled the work has already been done for you. If you need a more timely excuse for building one of these, the Fourth of July is a little bit closer, which should work in a pinch as an excuse to build something crazy even if you’re not American.

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Old Nixie Display Rides Again As 3D-Printer Filament Meter

May 9, 2019 by Dan Maloney 9 Comments

We’re not sure about the name of this Nixie tube filament meter that [Scott M. Baker] built. He calls it a “filadometer”, perhaps a portmanteau of “filament” and “odometer”, in which case it makes sense. It may not flow trippingly from the tongue and we can’t come up with anything better, but whatever moniker you use it’s actually a pretty cool build.

The filadometer started life as something completely different and utterly typical for Nixie tube projects – a temperature and humidity gauge. [Scott] decided to recycle the eight-tube display to keep track of his Prusa, and in doing so he reveals a pretty remarkable degree of forethought in his design process. The original Nixie display has all the usual trappings – the driver chips, the shift registers, and the high voltage power supply. What stands out is the modularity of his design: the tube sockets and drivers live on a backplane PCB, with a Raspberry Pi and a separate HV supply board plugging into it. The original display had a Model B Pi, so there was plenty of room for a new Zero W. A new printed case and a little programming to capture the filament use from Octoprint is all it took to put this nifty little build back in action. The video below shows the details.

We’re always excited to see new videos from [Scott] because we learn so much from looking over his virtual shoulder. If you haven’t checked out his stuff, take a look at his homage to the 8″ floppy or his dual-port memory hack for retro gaming.

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