Bend Your Vase Mode Prints By Hacking The GCode

February 22, 2022 by Dave Rowntree 3 Comments

[Stefan] from CNCKitchen wanted to make some bendy tubes for a window-mountable ball run, and rather than coming up with some bent tube models, it seemed there might be a different way to achieve the desired outcome. Starting with a simple tube model designed to be quickly printed in vase mode, he wrote a Python script which read in the G-Code, and modified it allow it to be bent along a spline path.

Vase mode works by slowly ramping up the Z-axis as the extruder follows the object outline, but the slicing process is still essentially the same, with the object sliced in a plane parallel to the bed. Whilst this non-planar method moves the Z-axis in sync with the horizontal motion (although currently limited to only one plane of distortion, which simplifies the maths a bit) it is we guess still technically a planar solution, but just an inclined plane. But we digress, non-planar in this context merely means not parallel to the bed, and we’ll roll with that.

[Stefan] explains that there are quite a few difficulties with this approach. The first issue is that on the inside of the bend, the material flow rate needed to be scaled back to compensate. But the main problem stems from the design of the extruder itself. Intended for operating parallel to the bed, there are often a few structures in the way of operating at an angle, such as fan mounts, and the hotend itself. By selecting an appropriate machine and tweaking it a bit, [Stefan] managed to get it to work at angles up to 30 degrees off the horizontal plane. One annoyance was that the stock nozzle shape of his E3D Volcano hotend didn’t lend itself to operating at such an inclination, so he needed to mount an older V6-style tip with an adapter. After a lot of tuning and fails, it did work and the final goal was achieved! If you want to try this for yourselves, the code for this can be found on the project GitHub.

If you want to learn more about non-planar printing, we’ve covered the process of non-planar slicing a while back, and if you think your 2.5D printer doesn’t quite have the range for really funky print paths, then you may want to look into a robot arm based printer instead.

Continue reading “Bend Your Vase Mode Prints By Hacking The GCode” →

A PNG Based Circuit Simulator

February 16, 2022 by Matthew Carlson 12 Comments

We’re sure thousands of hours have been spent in Minecraft implementing digital logic. Inspired by that, [lynnpepin] created a digital logic simulator named Reso that is based on pixels rather than voxels.

There are a few clever things here. First, different colors represent different parts. There are three different colors of wire, output and input wires, XOR gates, and AND gates. OR gates are just output wires, which or all the input wires together. By implementing these gates, Reso is, by definition, Turing complete. Since it’s just a PNG, it is trivial to open it up in GIMP and copy and paste one bit of the circuit multiple times. The different color wires are mainly to help route in a 2d plane, as you don’t have vias. Currently, the image compiles into a graph that is executed. [Lynn] chose code readability and ease of prototyping over premature optimization, so the code isn’t particularly fast. But it is pretty fun, squinting at the pixels that make up the adders and clocks he has on his blog. After giving Reso your image, it outputs a series of images that enumerate the state for several states.

The code is available on Github, and a Rust version has already been written that offers some impressive speed improvements at the expense of not being at feature parity yet. If MS-Paint isn’t your IDE of choice, perhaps a more Javascript-based digital logic simulator might be more to your taste.

Wordle Reverse-Engineering And Automated Solving

February 8, 2022 by Dave Rowntree 15 Comments

Simplified Absurdle decision tree for a single letter guess from a set of three possible options

We don’t know about you, but we have mixed feelings about online puzzle fads. On one hand, they are great tool to help keep one sharp, but they’re just everywhere. The latest social-media driven fad, Wordle, may be a little bit too prevalent for our liking, with social media timelines stuffed with updates about the thing. [Ed Locard] was getting a bit miffed with friends’ constant posts about ‘Today’s Wordle’, and was hoping they’d get back to posting pictures of their dogs instead, so did what any self-respecting hacker would do, and wrote a python script to automate solving Wordle puzzles, in a likely futile attempt to get them to stop posting.

Actually, [Ed] was more interested in building a solver for a related game, Absurdle, which is described as an adversarial variant of Wordle. This doesn’t actually select a single word, but uses your guesses so far to narrow down a large pool of possible words, keeping you guessing for longer. Which is pretty mean of it. Anyway, [Ed] came up with a tool called Pyrdle, (GitHub project) which is essentially a command version of Absurdle, that has the capability of also solving Wordle as a byproduct. It turns out the JS implementation of Wordle holds the entire possible wordlist, client-side, so the answer is already sitting in your browser. The real interest part of this project is the approach to automated problem solving of puzzles with a very large potential set of solutions. This makes for an interesting read, and infinitely more so than reading yet another Wordle post.

And one final note; if you’re not at all onboard with this, love Wordle, and can’t get enough, you might like to install [brackendawson]’s comically titled (command) notfoundle shell handler, for some puzzling feedback on your command-line slip-ups. Well, it amused us anyway.

Puzzle projects hit these pages once in a while. Here’s the annual Xmas GCHQ puzzle, If you’re more into physical puzzles, with an electronics focus (and can solder) check out the DEF CON 29 puzzle badge!

“Lazier” Web Scraping Is Better Web Scraping

February 7, 2022 by Donald Papp 13 Comments

Ever needed to get data from a web page? Parsing the content for data is called web scraping, and [Doug Guthrie] has a few tips for making the process of digging data out of a web page simpler and more efficient, complete with code examples in Python. He uses getting data from Yahoo Finance as an example, because it’s apparently a pretty common use case judging by how often questions about it pop up on Stack Overflow. The general concepts are pretty widely applicable, however.

[Doug] shows that while parsing a web page for a specific piece of data (for example, a stock price) is not difficult, there are sometimes easier and faster ways to go about it. In the case of Yahoo Finance, the web page most of us look at isn’t really the actual source of the data being displayed, it’s just a front end.

One way to more efficiently scrape data is to get to the data’s source. In the case of Yahoo Finance, the data displayed on a web page comes from a JavaScript variable that is perfectly accessible to the end user, and much easier to parse and work with. Another way is to go one level lower, and retrieve JSON-formatted data from the same place that the front-end web page does; ignoring the front end altogether and essentially treating it as an unofficial API. Either way is not only easier than parsing the end result, but faster and more reliable, to boot.

How does one find these resources? [Doug] gives some great tips on how exactly to do so, including how to use a web browser’s developer tools to ferret out XHR requests. These methods won’t work for everything, but they are definitely worth looking into to see if they are an option. Another resource to keep in mind is woob (web outside of browsers), which has an impressive list of back ends available for reading and interacting with web content. So if you need data for your program, but it’s on a web page? Don’t let that stop you!

CadQuery Comes Of Age

February 4, 2022 by Dave Rowntree 66 Comments

Now, we know what some of you are going to say — “Oh man, not another programmatic CAD tool, what’s wrong with OpenSCAD?” — and you may be right, but maybe hold on a bit and take a look at this one, because we think that it’s now pretty awesome! OpenSCAD is great, we use it all the time round these parts, but it is a bit, you know, weird in places. Then along comes CadQuery, and blows it out of the water ease-of-use and functionality wise. Now, we’ve seen a few mentions of CadQuery over the years, and finally it’s become a full-blown toolset in its own right, complete with a graphical frontend/editor, CQ-editor. No odd dependencies on FreeCAD to be seen! That said, installing FreeCAD is not a bad thing either.

The goal is to have the CadQuery script that produces this object be as close as possible to the English phrase a human would use.

Continue reading “CadQuery Comes Of Age” →

Python Web Proxy Convinces Sonos To Stream YouTube

February 4, 2022 by Dave Rowntree 22 Comments

[Maurice-Michel Didelot] owns a Sonos smart speaker, and was lamenting the devices inability (or plain unwillingness) to stream music from online sources without using a subscription service. YouTube Music will work, but being a subscription product there is a monthly fee, which sucks since you can listen to plenty of content on YouTube for free. [Maurice] decided that the way forward was to dig into how the Sonos firmware accesses ‘web radio’ sources, and see if that could be leveraged to stream audio from YouTube via some kind of on-the-fly stream conversion process.

What? No MP4 support for web radio? Curses!

So let’s dig in to how [Maurice] chose to approach this. The smart speaker can be configured to add various streaming audio sources, and allows you add custom sources for those. The Sonos firmware supports a variety of audio codecs, besides MP3, but YouTube uses the MP4 format. Sonos won’t handle that from a web radio source, so what was there to do, but make a custom converter?

After a little digging, it was determined that Sonos supports AAC encoding (which is how MP4 encodes audio) but needs it wrapped in an ADTS (Audio Data Transport Stream) container. By building a reverse web-proxy application, in python using Flask, it was straightforward enough to grab the YouTube video ID from the web radio request, forward a request to YouTube using a modified version of pytube tweaked to not download the video, but stream it. Pytube enabled [Maurice] to extract the AAC audio ‘atoms’ from the MP4 container, and then wrap them up with ADTS and forward them onto the Sonos device, which happily thinks it’s just a plain old MP3 radio stream, even if it isn’t.

Sonos doesn’t have the best reputation, let’s say, but you can’t deny that there’s some pretty slick tech going on inside. Here’s a neat hack we covered last year, adding Sonos support to an old school speaker, and a nice teardown of a IKEA Sonos-compatible unit, which uses some neat design hacks.

Thanks [mip] for the tip!

Featured image by Charles Deluvio on Unsplash.

Make Your Python CLI Tools Pop With Rich

January 19, 2022 by Matthew Carlson 6 Comments

It seems as though more and more of the simple command-line tools and small scripts that used to be bash or small c programs are slowly turning into python programs. Of course, we will just have to wait and see if this ultimately turns out to be a good idea. But in the meantime, next time you’re revamping or writing a new tool, why not spice it up with Rich?

Rich is a python library written by [Will McGugan] that offers text formatting, colors, graphs, progress bars, markdown, syntax highlighting, charts, and more through the power of ANSI codes. The best part is that it works with macOS, Windows, and Linux. In addition, it offers logging solutions that work out of the box. One of the best features of Rich is the inspect functionality. You can pass in an object, and it will use reflection to print a beautiful chart detailing what exactly the object is, helpful in debugging. The other feature is the traceback, which shows a formatted and annotated snapshot of relevant code on the stack during exceptions.

The source itself is well-written python with comments and typing information. There’s a good chance you’ll pick up a trick or two reading through it. Rich is used to build Textual (also by [Will]), which aims to be a GUI API that runs in the terminal. It served as an excellent example of what Rich is capable of. It is incredible how long these protocols have been around. [Will] even ran Rich on a Teletype Model 33. If you’re working with a bit more of a constrained environment, why not bring some color to your Arduino serial terminal?