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.
It’s a special gut-dropping, grumbly moment that most who use 3d printers know all too well. When you check on your 13-hour print, only to see that it failed printing several hundred layers ago. [Stephan] from [CNC Kitchen] has a few clever tricks to resume failed prints.
It starts when you discover your print has failed and whether the part is still attached to the bed. If it has detached, the best you can do is whip out your calipers to get a reasonably accurate measurement of how much has been printed. Then slice off the already printed section, print the remainder, and glue the two parts together. If your part is attached to your print bed and you haven’t shifted the plate (if it is removable), start by removing any blemishes on the top layer. That will make it smooth and predictable as it’s starting a new print, just on top of an existing one. Measuring the height that has been printed is tricky since you cannot remove it. Calipers of sufficient length can use their depth function, but you might also be able to do a visual inspection if the geometry is unique enough. After you load up your model in a G-Code viewer, go through it layer by layer until you find what matches what has already been printed.
The last (and perhaps most clever) is to use the printer as a makeshift CMM (coordinate measuring machine). You manually step the printer until it touches the top of the part, then read the z-axis height via a screen or M114 command. A quick edit to the raw G-Code gives you a new file that will resume precisely what it was doing before. If you can’t rehome because the head can’t clear the part, [Stephan] walks you through setting the home on your printer manually.
Don’t get too excited, a 3D printed radiation shield won’t keep you from getting irradiated during WWIII. But until the Doomsday Clock starts clanging its midnight bell, you can use one to improve the accuracy of your homebrew weather monitoring station by keeping the sun from heating up your temperature sensor. But how much does it help, and what material should you load up in your extruder to make one? Those questions, and more, are the topic of a fascinating whitepaper included in the upcoming volume of HardwareX.
Design and Implementation of 3-D Printed Radiation Shields for Environmental Sensors not only tests how effective these low-cost shields are when compared to an uncovered sensor, but addresses specific concerns in regards to leaving 3D printed parts out in the elements. Readers who’ve squirted out a few rolls worth of the stuff will know that common polylactic acid (PLA) filament, while easy to work with and affordable, isn’t known for its resilience. In fact, one of the advertised properties of the renewable plastic is that it’s biodegradable (theoretically, at least), so leaving it outside for any length of time sounds like it’s bound to go poorly.
PLA’s mechanical strength dropped rapidly.
To make a long story short, it does. While the team demonstrated that the PLA printed radiation shield absolutely helped preserve the accuracy of the temperature and humidity sensors mounted inside of it, the structure itself began to deform rapidly from UV exposure. Further tests determined that the mechanical strength of the PLA showed a notable reduction in as little as 30 days, and a sharp decline after 90 days.
Luckily, there was more than one plastic horse in the race. In addition to the PLA printed shield, the team also tested a version printed in acrylonitrile styrene acrylate (ASA) which fared far better. There was no visible deformation of the shield, and after 90 days, the reduction in mechanical strength was negligible. It even performed a bit better when it came to shielding the temperature sensor, which the team believes may be due to the material’s optical transmission properties.
So there you have it: a 3D printed radiation shield will absolutely improve the accuracy of your weather sensors, but if you want it to last outside, PLA just isn’t going to cut it. On the other hand, you could also save yourself a whole lot of time by just using a stack of plant saucers. Whatever works.
[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.
Over the years we’ve seen many small computer boards of various abilities, among them many powerful enough to be almost-useful Linux general purpose computers. We’ve also seen more than a few computers that claimed the impossible, usually an amazing spec for a tiny price tag. Here for once is a small computer that’s neither of those two; a minimum viable Linux handheld terminal whose $15 USD price tag is openly discussed as a target price for a large production run rather than touted as its retail price.
It’s the work of legendary former Hackaday writer [Brian Benchoff], and instead of being merely a PCB it’s a fully usable computer with case, keyboard and display. It’s based upon an Allwinner F1C100s SoC, it’s powered by AAA cells, and it sports a split rubber keyboard that likely builds on his previous experience with the VT-69 portable RS-232 terminal. On the back is a USB port and an SD reader, and in the centre of the front panel lies a 320 x 240 pixel display. It’s important to note that this is not intended to run a GUI, while it’s DOOM-capable it remains very much a command-line Linux tool. Perhaps most interestingly it’s claimed that all the parts are available in quantity here in the chip shortage, so maybe there’s even a chance we might see it as more than a project. We can hope.
Last week brought the story of a group of crypto enthusiasts who paid well over the going rate for a rare sci-fi book, then proposed encoding scans of all its pages in a blockchain before making and selling NFTs of them. To guarantee their rarity the book was then to be burned. Aside from the questionable imagery surrounding book burning in general, one of the sources of mirth in the story was their mistaken idea that in buying a copy of a rare book they had also acquired its copyright rather than simply paying too much for a book.
It’s an excuse for a good laugh, but it’s also an opportunity to talk about copyright as it affects our community. I’m not a lawyer and I’m not here to give legal advice. Instead this is based on the working knowledge gathered over decades working in the content publishing industries. Continue reading “Copyright, What You Need To Know”→
Join Hackaday Editor-in-Chief Elliot Williams and Staff Writer Dan Maloney for this week’s podcast as we talk about Elliot’s “defection” to another podcast, the pros and cons of CNC builds, and making Nixie clocks better with more clicking. We’ll explore how citizen scientists are keeping a finger on the pulse of planet Earth, watch a 2D stepper go through its paces, and figure out how a minimalist addressable LED strip works. From solving a Rubik’s cube to answering the age-old question, “Does a watched pot boil?” — spoiler alert: if it’s well designed, yes — this episode has something for everyone.
Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!
