Glia Is Making Open Medical Devices, And You Can Help

The Glia project aims to create a suite of free and open-source medical equipment that can be assembled cheaply and easily when and where it’s needed. Even essential tools like stethoscopes and tourniquets can be difficult to acquire in certain parts of the world, especially during times of war or civil unrest. But armed with a 3D printer and the team’s open-source designs, an ad-hoc factory can start producing these lifesaving tools anywhere on the planet.

Glia member [Tarek Loubani] has recently written a blog post discussing the team’s latest release: an otoscope that can be built for as little as $5. Even if you don’t recognize the name, you’ve almost certainly seen one of them in use. The otoscope is used to look inside the ear and can be invaluable in diagnosing illnesses, especially in children. Unfortunately, while this iconic piece of equipment is quite simple on a technical level, professional-quality versions can cost hundreds of dollars.

Now to be fair, you’ll need quite a bit more than just the 3D printed parts to assemble the device. The final product requires some electrical components such as a battery holder, rocker switch, and LED. It also requires a custom lens, though the Glia team has thought ahead here and provided the files for printable jigs that will allow you to cut a larger lens down to the size required by their otoscope. In a situation where you might have to improvise with what you have, that’s a very clever design element.

So far the team is very happy with how the otoscope performs, but they’ve run into a bit of a logistical snag. It turns out that early work on the project was done in the web-based TinkerCAD, which isn’t quite in line with the team’s goals of keeping everything free and open. They’d like some assistance in recreating the STLs in FreeCAD or OpenSCAD so they’re easier to modify down the road. So if you’re a FOSS CAD master and want to earn some positive karma, head over to the GitHub page for the project and put those skills to use.

We’ve previously covered Glia’s work with 3D printed tourniquets to treat gunshot wounds, a project that led to [Tarek] himself being shot by a sniper while attempting to field test the design in Gaza. If that’s not commitment to the principles of open-source hardware, we don’t know what is.

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Try NopSCADlib For Your Next OpenSCAD Project

Most readers of this site are familiar by now with the OpenSCAD 3D modeling software, where you can write code to create 3D models. You may have even used OpenSCAD to output some STL files for your 3D printer. But for years now, [nophead] has been pushing OpenSCAD further than most, creating some complex utility and parts libraries to help with modeling, and a suite of Python scripts that generate printable STLs, laser-ready DXFs, bills of material, and human-readable assembly instructions complete with PNG imagery of exploded-view sub-assemblies.

Recently [nophead] tidied all of this OpenSCAD infrastructure up and released it on GitHub as NopSCADlib. You can find out more by browsing through the example projects and README file in the repository, and by reading the announcement blog post on the HydraRaptor blog. Some functionality highlights include:

  • a large parts library full of motors, buttons, smooth rod, et cetera
  • many utility functions to help with chamfers, fillets, precision holes, sub-assemblies, and BOM generation
  • Python scripts to automate the output of STLs, DXFs, and BOMs
  • automatic creation of documentation from Markdown embedded in your OpenSCAD files
  • automatic rendering of exploded subassemblies

All that’s missing is a nice Makefile to tie it all together! Try it out for your next project if you – like us – get giddy at the thought of putting your 3D projects into version control before “compiling” them into the real world.

We’ve discussed some complex OpenSCAD before: Mastering OpenSCAD Workflow, and An OpenSCAD Mini-ITX Computer Case.

Volkswagen Tools Turned To The Space Age

The Volkswagen Beetle, and yes the bus and the sexiest car ever made, are cars meant for the people. You can pull the engine out with a strong friend, and you can fix anything in an old Volkswagen. VW realized this, because in the 1950s and ’60s, they came up with plans for tools designed to tear apart an old VW, and these tools were meant to be manufactured in a local shop. That really turns that right to repair on its head, doesn’t it?

While working on his van, [Justin Miller] came across a reference to one of these tools meant to be made at home. The VW 681 is a seal puller, designed to be manufactured out of bar stock. It’s an old design, but now we have interesting tools like 3D printers and parametric CAD programs. Instead of making one of these DIY seal pullers with a grinder, [Justin] brought this tool from the space age into the modern age. He took the design, modelled it in OpenSCAD, and printed it out.

The VW reference book that lists this tool is Workshop Equipment for Local Manufacture, and for this seal puller, it gives perfectly dimensioned drawings  that are easily modelled with a few lines of code. The only real trouble is filing down the pointy bit of the puller, but a bit of boolean operations fixed that problem. After 15 minutes of printing and a few hours finding the right documentation and writing fifteen lines of code, [justin] had a plastic VW 681 in his hands. Yes, it was probably a waste of time as a regular seal puller could have done the job, but it’s an excellent example of what can happen when manufacturers support their local repairman.

OpenSCAD Gives You Parametric Boxes

OpenSCAD is one of the most powerful 3d modeling applications around. Its beauty is in its simplicity; if you need a box, you can just write the code for a box. If you need some bit of plastic to keep your 3D printer running, you can just write the code for that bit of plastic. Like all programming languages, OpenSCAD is only really powerful if you have a huge back-catalog of various components ready for reuse. That’s where [Mark]’s library for hinged boxes comes in handy. Every type of box you would ever want to create, from boxes with covers, magnet closures, or cases for your glasses is easily accessible with just a few lines of code.

The work presented here is an OpenSCAD script to generate two-piece hinged boxes, with rounded corners, a lid, interlocking rims, and optional snap fit, magnet, or screw closures. As you would expect from OpenSCAD, everything in this script is parametric. You can change any measurement or simply delete entire sections of the box.

The included examples consist of a small mini-Altoids tin-sized ‘Bee Box’ with a snap-fit lid. All of the relevant dimensions of the snap-fit lid are variables. Other examples include an eyeglass case and a box for small parts storage that interlock. If you have a few rolls of filament, a lot of time on your hands, and want to organize your workbench, you could do worse than checking out a few of these OpenSCAD boxes.

When Unfolding An STL In Software, Math Isn’t The Tricky Part

Some time ago, [Trammell Hudson] took a shot at creating a tool that unfolds 3D models in STL format and outputs a color-coded 2D pattern that can be cut out using a laser cutter. With a little bending and gluing, the 3D model can be re-created out of paper or cardboard.

There are of course other and more full-featured tools for unfolding 3D models: Pepakura is used by many, but is not free and is Windows only. There is also a Blender extension called Paper Model that exists to export 3D shapes as paper models.

What’s interesting about [Trammell]’s project are the things he discovered while making it. The process of unfolding an STL may be conceptually simple, but the actual implementation is a bit tricky in ways that have little to do with number crunching.

For example, in a logical sense it doesn’t matter much where the software chooses to start the unfolding process, but in practice some start points yield much tighter groups of shapes that are easier to work with. Also, his software doesn’t optimize folding patterns, so sometimes the software will split a shape along a perfectly logical (but non-intuitive to a human) line and it can be difficult to figure out which pieces are supposed to attach where. The software remains in beta, but those who are interested can find it hosted on GitHub. It turns out that it’s actually quite challenging to turn a 3D model into an unfolded shape that still carries visual cues or resemblances to the original. Adding things like glue tabs in sensible places isn’t trivial, either.

Tools to unfold 3D models feature prominently in the prop-making world, and it’s only one of the several reasons an economical desktop cutter might be a useful addition to one’s workshop.

Mastering OpenSCAD Workflow

As you may have noticed in our coverage, we’re big fans of OpenSCAD around these parts. The fact that several of the Hackaday writers organically found and started using the parametric CAD package on their own is not only a testament to our carefully cultivated hive mind but also to the type of people it appeals to. Hackers love it because it allows you to model physical objects as if you were writing software: models are expressed in code, and its plain text source files can be managed with tools like git and make. If you’re a real Pinball Wizard you could design objects and export them to STL without ever using a graphical interface.

But as you might expect, with such power comes a considerable learning curve. OpenSCAD devotee [Uri Shaked] recently wrote in to share with us his workflow for designing complex interacting mechanisms, which serves as an excellent primer to the world of parametric design. From animating your models to recreating the “vitamins” of your build, his post contains plenty of tips that can help both new and veteran OpenSCAD users alike.

Perhaps the biggest takeaway from his post is that you should be thinking of your projects as a whole, rather than as individual models. [Uri] recalls his early attempts at designing mechanisms: designing each component individually, printing it out, and only then finding out if it fits together with the other pieces. This method of trial and error is probably familiar to anyone who’s designed their own 3D printed parts — but it’s slow and wastes materials. The alternative, as he explains it, is to design all of the pieces at the same time and “assemble” them virtually. This will allow you to check clearances and fitment without dedicating the time and materials to test it in the real world.

In fact, as [Uri] explains, you’re better off spending your time bringing real-world parts into OpenSCAD. By carefully measuring the hardware components you want to interact with (servos, gears, switches, etc), you can create facsimiles of them to use as a reference in your OpenSCAD project. As time goes on, you can build up your own library of drop-in reference models which will accelerate future designs.

He also spends a little time talking about something that doesn’t seem to be terribly well known even among the OpenSCAD converts: you don’t have to use the built-in editor if you don’t want to. Since OpenSCAD source code files are plain text, you can write them in whatever editor you like. The OpenSCAD model viewer even has an option specifically for this scenario, which will cause it to update the rendered preview as soon as it detects the source has been updated. For [Uri] this means he can create his designs in Visual Studio Code with a constantly updating preview in another window.

If you’re looking for examples of what the parametric capabilities of OpenSCAD can do for you, we’ve got no shortage of excellent examples. From creating customized computer cases to saving time by using mathematically derived components. Our very own [Elliot Williams] even has a write up about that most glorious of OpenSCAD commands: hull().

An OpenSCAD Mini-ITX Computer Case

We’re no strangers to 3D printed enclosures here at Hackaday. From the plethora of printed Raspberry Pi cases out there to custom enclosures for electronic projects, small plastic boxes turn out to be an excellent application for desktop 3D printing. But as printers get bigger and filament gets cheaper, those little boxes don’t always need to be so little. We aren’t talking about running off boxes for your sneaker collection either, if you’ve got the time and the print volume, you could whip up an enclosure for your PC.

[Nirav Patel] writes in to share his impressive 3D printed Mini-ITX computer case project, which would be a neat enough trick in its own right, but he took the concept one step farther and made it a parametric design in OpenSCAD. This allows the user to input their particular hardware configuration and receive STL files for a bespoke case. The list of supported hardware isn’t that long yet, but with the OpenSCAD code up on GitHub and released under the BSD license, hopefully the community can improve on that as time goes on.

To keep things simple (and strong), [Nirav] implemented what he refers to as a “bucket” design. The majority of the case is a single print, which does take a long time (just shy of 40 hours on his Prusa i3 MK3), but nearly eliminates any post-printing assembly. Only the optional feet and the lid need to be printed separately. Threaded inserts are used throughout the design for mounting hardware, so you don’t run the risk of blowing out the printed holes during hardware changes or upgrades.

A particularly neat feature, and a testament to the power of OpenSCAD, is the fact that the case’s internal volume is calculated and embossed into the side of the design. Does this have any practical purpose? Not exactly, but [Nirav] thought it would be appealing to the Mini-ITX case modding community which apparently measures their accomplishments in liters of volume.

We’ve seen a 3D printed computer case before, but it used acrylic sheets and couldn’t be made without a large format printer. There’s something to be said for a project that can be completed on the hacker community’s favorite printer.