a 3d mesh of a rabbit, and a knit version of the same

Knitting Software Automatically Converts 3D Models Into Machine-knit Stuffies

June 14, 2019 by Brian Boucheron 20 Comments

We’ve seen our fair share of interesting knitting hacks here at Hackaday. There has been a lot of creative space explored while mashing computers into knitting machines and vice versa, but for the most part the resulting knit goods all tend to be a bit… two-dimensional. The mechanical reality of knitting and hobbyist-level knitting machines just tends to lend itself to working with a simple grid of pixels in a flat plane.

However, a team at the [Carnegie Mellon Textiles Lab] have been taking the world of computer-controlled knitting from two dimensions to three, with software that can create knitting patterns for most any 3D model you feed it. Think of it like your standard 3D printing slicer software, except instead of simple layers of thermoplastics it generates complex multi-dimensional chains of knits and purls with yarn and 100% stuffing infill.

The details are discussed and very well illustrated in their paper entitled Automatic Machine Knitting of 3D Meshes and a video (unfortunately not embeddable) shows the software interface in action, along with some of the stuffing process and the final adorable (ok they’re a little creepy too) stuffed shapes.

Since the publication of their paper, [the Textiles Lab] has also released an open-source version of their autoknit software on GitHub. Although the compilation and installation steps look non-trivial, the actual interface seems approachable by a dedicated hobbyist. Anyone comfortable with 3D slicer software should be able to load a model, define the two seams necessary to close the shape, which will need to be manually sewn after stuffing, and output the knitting machine code.

Previous knits: the Knit Universe, Bike-driven Scarf Knitter, Knitted Circuit Board.

Breakout Board Becomes Pogo Pin Programmer

May 18, 2019 by Brian McEvoy 9 Comments

Making a programming jig becomes exponentially more difficult after two pins and who would even consider building one if they were not setting up more than twenty boards? If it were easy for novices to construct jigs, we might all have a quiver of them on the shelf next to our microprocessors. Honestly, a tackle box full of homemade programming fixtures sounds pretty chic. The next advantage to ditching the demo boards is that bare processors take up less room and don’t draw power for unnecessary components like unused voltage regulators and LEDs. [Albert David] improves the return-on-time-investment factor by showing us how to repurpose a WeMos board to program a bare ESP8266 module.

[Albert]’s concept can apply to many other surface-mount chips and modules. The first step is to buy a demo board which hosts a programmable part and remove that part. Since you’ve exposed some solder pads in the process, put pogo pins in their place. Pogo pins are small spring-loaded probes that can be surface mounted or through-hole. We’ve used them for programming gorgeous badges and places where the ESP8266 has already been installed. When you are ready to install your software, clamp your Franken-porcupine to the controller and upload like normal. Rinse, wash, repeat. We even get a view of the clamp [Albert] uses.

Raspberry Pi Streams Music Using Only The Default Linux Tools

May 2, 2019 by Bryan Cockfield 13 Comments

Getting a home music streaming system off the ground is typically a straightforward task. Using Apple devices with Airplay makes this task trivial, but if you’re a computing purist like [Connor] who runs a Linux machine and wants to keep it light on extra packages, the task gets complicated quickly. His goal is to bring audio streaming to all Linux platforms without the need to install a lot of extra software. This approach is friendly to light-footprint devices like the Raspberry Pi that he used in his proof of concept.

[Connor] created a set of scripts which allow streaming from any UNIX (or UNIX-like) machines, using only dependencies that a typical OS install would already have. His Raspberry Pi is the base station and streams to his laptop, but he notes that this will work between virtually any UNIX or Linux machine. The only limitation is what FFmpeg can or can’t play.

We definitely can appreciate a principled approach to software and its use, although it does seem that most people don’t have this issue at the forefront of their minds. This results in a lot of software that is bulky, making it difficult to maintain, use, or even know what it does, and also makes it harder for those of us that don’t want to use that type of software to find working solutions to other problems. It’s noble that [Connor] was able to create something without sacrificing any principles.

Easy Git Repository Summaries With Web-git-sum

March 25, 2019 by Donald Papp 16 Comments

For those hosting their own git repositories there are a number of solutions for creating convenient web-accessible front ends, but [mitxela] wasn’t quite satisfied with any of them. After trying a number of alternatives and reflecting on his requirements, he realized that all he really needed was a summary page listing the latest commits, and a file tree with a list of branches and tags. To accomplish this, he created web-git-sum. It’s a bash script that runs on git’s post-receive hook and generates only two files: a summary page and an index of the repository. You can see a demo of the output at git.mitxela.com.

[mitxela]’s writeup goes into some detail on how git repositories work, how those repositories are served over HTTP, and covers a few of the different options for providing convenient and accessible web front ends. Not all repositories are alike, and what works well for one may not work or scale well for another.

Intrigued by the idea of a private git server? We covered exactly how to set one up (spoiler: it’s really easy.)

Show Your Skills With A Bootable CV

March 23, 2019 by Jenny List 10 Comments

It’s a thankless task, searching for a job. You send off your CV, or resume, and it joins a thousand other destined for the round file. What on earth can you do to make your career stand out, and catch the eye of the recruiter?

Your bootable CV isn't eye-catching if the recruiter uses GitHub to view the PDF. — Your bootable CV isn’t eye-catching if the recruiter uses GitHub to view the PDF.

If you are [Pablo Jiménez Mateo], the answer is straightforward enough. Simply combine the document as a PDF with an x86 bootloader, to make a readable document that will also boot an x86 computer system. He can do this relatively easily by prepending the bootloader file to the PDF, as long as the “%PDF” header of the CV remains within the first 1024 bytes it will remain a readable document. Which it does, though as our GitHub screenshot shows, not in all PDF readers.

A bootable PDF is pretty cool and we have to salute his effort in getting it in front of us in the hope of career boost, but it would be fair to admit that it’s a trick that has been done before. So it’s time to turn attention to the bootloader itself, whose code comes in the form of an extremely well-commented assembly file that loads some sprites and a border to a VGA screen that looks as though it might be the first room in a top-down adventure game. Through the code we can gain an appreciation of just how simple a bootloader can be, and that in itself makes this project worth a second look.

If writing your own bootloader interests you, that’s certainly a subject we’ve covered in the past. It’s possible to make bootable images very small indeed, even down to fitting in a Tweet.

“Good Code Documents Itself” And Other Hilarious Jokes You Shouldn’t Tell Yourself

March 5, 2019 by Sven Gregori 159 Comments

Code documentation — is there anything more exciting than spending your time writing extensive comments? If I had to guess, your answer is probably somewhere along the lines of “uhm, yes, everything is more exciting than that”. Plus, requesting to document your code is almost like an insult to your well thought out design, this beautiful creation you implemented so carefully that it just has to be obvious what is happening. Writing about it is just redundant, the code is all you need.

As a result, no matter if it’s some open source side project or professional software development, code documentation usually comes in two flavors: absent and useless. The dislike for documenting ones code seems universal among programmers of any field or language, no matter where in the world they are. And it’s understandable, after all, you’re in it for the coding, implementing all the fun stuff. If you wanted to tell stories, you would have chosen a different path in life.

This reluctance has even formed whole new paradigms and philosophies claiming how comments are actually harmful, and anyone trying to weasel their way out of it can now happily rehash all those claims. But, to exaggerate a bit, we’re essentially villainizing information this way. While it is true that comments can be counterproductive, it’s more the fundamental attitude towards them that causes the harm here.

In the end, code documentation is a lot like error handling, we are told early on how it’s important and necessary, but we fail to understand why and instead grow to resent doing it again for that same old teacher, supervisor, or annoying teammate. But just like error handling, we are the ones who can actually benefit the most from it — if done right. But in order to do it right, we need to face some harsh truths and start admitting that there is no such thing as self-documenting code, and maybe we simply don’t understand what we’re actually doing if we can’t manage to write a few words about it.

So let’s burst some bubbles!

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Tiny Ray Tracer Fits In 64 Bytes

November 21, 2018 by Al Williams 51 Comments

Throughout human history, people try to make the biggest, the fastest, and — sometimes — the smallest. [Hellmood] falls into the latter category and proves it with a 64 byte interactive 3D raycasting application for MSDOS.

Why MSDOS? We suppose why not? The .COM file format is lean, and you can take over everything without a lot of work. If the program were huge, it wouldn’t be very impressive. There are 64 shades of gray which is odd looking these days, however there are versions that use various color palettes and each one fits in 64 bytes or less. There’s even mouse control and you can see the results in the video below.

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