Have you ever wondered what’s actually going on inside the hotend of your 3D printer? It doesn’t seem like much of a mystery — the filament gets melty, it gets squeezed out by the pressure of the incoming unmelty filament, and lather, rinse, repeat. Or is there perhaps more to the story?
To find out, a team from the University of Stuttgart led by [Marc Kreutzbruck] took the unusual step of putting the business end of a 3D printer into a CT scanner, to get a detailed look at what’s actually going on in there. The test setup consisted of a Bondtech LGX extruder and an E3D V6 hot end mounted to a static frame. There was no need for X-Y-Z motion control during these experiments, but a load cell was added to measure extrusion force. The filament was a bit specialized — high-impact polystyrene (HIPS) mixed with a little bit of tungsten powder added (1% by volume) for better contrast to X-ray. The test system was small enough to be placed inside a micro CT scanner, which generated both 360-degree computed tomography images and 2D radiographs.
The observations made with this experimental setup were pretty eye-opening. The main take-home message is that higher filament speed translates to less contact area between the nozzle wall and the melt, thanks to an air gap between the solid filament and the metal of the nozzle. They also saw an increased tendency for the incoming filament to buckle at high extruder speeds, which matches up with practical experience. Also, filament speed is more determinative of print quality (as measured by extrusion force) than heater temperature is. Although both obviously play a role, they recommend that if higher print speed is needed, the best thing to optimize is hot end geometry, specifically an extended barrel to allow for sufficient melting time.
Earth-shattering stuff? Probably not, but it’s nice to see someone doing a systematic study on this, rather than relying on seat-of-the-pants observations. And the images are pretty cool too.
The degree to which computed tomography has been a boon to medical science is hard to overstate. CT scans give doctors a look inside the body that gives far more information about the spatial relationship of structures than a plain X-ray can. And as it turns out, CT scans are pretty handy for reverse engineering mystery electronic modules, too.
The fact that the mystery module in question is from Apollo-era test hardware leaves little room for surprise that [Ken Shirriff] is the person behind this fascinating little project. You’ll recall that [Ken] recently radiographically reverse engineered a pluggable module of unknown nature, using plain X-ray images taken at different angles to determine that the undocumented Motorola module was stuffed full of discrete components that formed part of a square wave to sine wave converter.
The module for this project, a flip-flop from Motorola and in the same form factor, went into an industrial CT scanner from an outfit called Lumafield, where X-rays were taken from multiple angles. The images were reassembled into a three-dimensional view by the scanner’s software, which gave a stunningly clear view of the components embedded within the module’s epoxy body. The cordwood construction method is obvious, and it’s pretty easy to tell what each component is. The transistors are obvious, as are the capacitors and diodes. The resistors were a little more subtle, though — careful examination revealed that some are carbon composition, while others are carbon film. It’s even possible to pick out which diodes are Zeners.
The CT scan data, along with some more traditional probing for component values, let [Ken] reverse engineer the whole circuit, which turned out to be a little different than a regular J-K flip-flop. Getting a non-destructive look inside feels a little like sitting alongside the engineers who originally built these things, which is pretty cool.
Is it just me or did January seem to last for about three months this year? A lot has happened since the turn of the decade 31 days ago, both in the normie world and in our space. But one of the biggest pieces of news in the hacker community is something that won’t even happen for four more months: Hackaday Belgrade. The annual conference in Hackaday’s home-away-from-home in Serbia was announced, and as usual, one had to be a very early bird to score discount tickets. Regular tickets are still on sale, but I suspect that won’t last long. The call for proposals for talks went out earlier in the month, and you should really consider standing up and telling the world what you know. Or tell them what you don’t know and want to find out – there’s no better way to make connections in this community, and no better place to do it.
Someone dropped a tip this week about the possible closing of Tanner Electronics, the venerable surplus dealer located in Carrollton, Texas, outside of Dallas and right around the corner from Dallas Makerspace. The report from someone visiting the store is that the owner has to either move the store or close it down. I spoke to someone at the store who didn’t identify herself, but she confirmed that they need to either downsize or close. She said they’re actively working with a realtor and are optimistic that they’ll find a space that fits their needs, but the clock is ticking – they only have until May to make the change. We covered Tanner’s in a 2015 article on “The Death of Surplus”. It would be sad to lose yet another surplus store; as much as we appreciate being able to buy anything and everything online, nothing beats the serendipity that can strike walking up and down aisles filled with old stuff. We wish them the best of luck.
Are you finding that the smartphone in your pocket is more soul-crushing than empowering? You’re not alone, and more and more people are trying a “digital detox” to free themselves from the constant stimulation. And there’s no better way to go about this than by turning your smartphone into a not-so-smart phone. Envelope, a paper cocoon for your phone, completely masks the screen, replacing it with a simple printed keypad. A companion app allows you to take and make phone calls or use the camera, plus provides a rudimentary clock, but that’s it. The app keeps track of how long you can go before unwrapping your phone and starting those sweet, sweet dopamine hits again. It reminds us a bit of the story we also saw this week about phone separation anxiety in school kids, and the steps schools are taking to mitigate that problem.
We saw a lot of articles this week on a LoRaWAN security vulnerability. The popular IoT network protocol has been billed as “secure by default”, but a white paper released by cybersecurity firm IOActive found a host of potential attack vectors. Their main beef seems to be that client devices which are physically accessible can be reverse engineered to reveal their encryption keys. They also point out the obvious step of taking the QR code off of client devices so an attacker can’t generate session keys for the device.
And finally, the mummy speaks! If you ever wondered what the voice of someone who lived 3,000 years ago sounded like, wonder no more. Using computed tomography (CT) data, scientists in the UK and Germany have recreated the vocal tract of Nesyamun, an Egyptian scribe and priest from the time of pharaoh Rameses XI. He died in his mid-50s, and his mummified remains have been studied since the 1800s. CT data was used to 3D-print Nesyamun’s larynx and nasopharynx, which was then placed atop a “Vocal Tract Organ”, possibly the strangest musical instrument in existence. The resulting vowel-like utterance is brief, to say the least, but it’s clear and strong, and it’s pretty impressive that we can recreate the voice of someone who lived and died three millennia ago.
Every once in a while we get nostalgic for the old days of computing. Here, we’re getting nostalgic for a past that wasn’t even our own, but will probably bring a smile to all the German hackers out there. c’t magazine has its first issue available on their website (PDF, via FTP), and it’s worth checking out even if you can’t read a word of German.
It’s dated November/December 1983, and you’re definitely hopping in the WABAC machine here. The cover image is a terminal computer project that you’re encouraged to build for yourself, and the magazine is filled with those characteristic early-computer-era ads, many of them for the physical keyboards that you’d need to make such a device. Later on, c’t would provide plans for a complete DIY PC with plotter, one of which we saw still running at the 2015 Berlin Vintage Computer Festival.
The issue is chock-full of code for you to type out into your own computer at home. If you didn’t have a computer, there are of course reviews of all of the popular models of the day; the TRS-80 Model 100 gets good marks. And if you need to buy a BASIC interpreter, there’s an article comparing Microsoft’s MBASIC with CBM’s CBASIC. A battle royale!
Other hot topics include modifications to make your ZX81’s video output sharper, the hassle of having to insert a coded dongle into your computer to run some software (an early anti-piracy method), and even a computer-music band that had (at least) a Commodore 64 and a CBM machine in their groovy arsenal.
It’s no secret that we like old computers, and their associated magazines. Whether you prefer your PDP-11’s physical or virtual, we’ve got you covered here. And if your nostalgia leans more Anglophone, check out this Byte magazine cover re-shoot.
There are a lot of ways to measure energy usage in the home, but most of them involve handling mains voltage. Not only that, but sometimes they require handling mains voltage before it gets through a breaker panel or fuse box, meaning that if you make a mistake there are a lot of bad things that can happen. [Yonas] has been working on this problem, and has come up with a non-invasive, safer way to monitor electricity consumption without having to work directly on live wires.
Please note that you should still not be working on mains voltage without proper training, but if you have the required know-how then the installation should be pretty straightforward. The project is based on the Spark Core, and uses clamp-on current sensors to measure energy use. The sensors wrap around the mains cable, meaning you don’t have to disconnect anything to hook them up. The backend runs on a LAMP server which could be a Raspberry Pi if you have one. [Yonas] runs it on a hosted server as a matter of preference.
All of the source code for this is available, and assuming you can get your hands on the current sensors this could be a great way to get started monitoring your energy usage in the house. Be sure to check out the video below for a demonstration of the operation of this device. Of course, if you have a gas line you’ll need this energy monitoring setup too.
What do you do when you’re dad’s a veterinarian, dumped an old x-ray machine in your garage, and you’re looking for an entry for The Hackaday Prize? Build a CT scanner, of course. At least that’s [movax]’s story.
[movax]’s dad included a few other goodies with the x-ray machine in the garage. There were film cassettes that included scintillators. By pointing a camera at these x-ray to visible light converting sheets, [movax] can take digital pictures with x-rays. From there, it’s just building a device to spin around an object and a lot – a lot – of math.
Interestinly, this is not the first time a DIY CT scanner has graced the pages of Hackaday. [Peter Jansen] built a machine from a radiation check source, a CMOS image sensor, and a beautiful arrangement of laser cut plywood. This did not use a proper x-ray tube; instead, [Peter] was using the strongest legally available check source (barium 133). The scan time for vegetables and fruit was still measured in days or hours, and he moved on to build an MRI machine.
With a real source of x-rays, [movax]’s machine will do much better than anything the barium-based build could muster, and with the right code and image analysis, this could be used as a real, useful CT scanner.
[Oliver] is using three different pieces of software to turn the DICOM images he received from his radiologist into a proper 3D model. The first two, Seg3D and ImageVis3D, are developed by the University of Utah Center for Integrative Biomedical Computing. Seg3D stitches all of the 2D images from an MRI or CT scan into a proper 3D format. ImageVis3D allows [Oliver] to peel off layers of his flesh, allowing him to export a file of just his skull, or a section of his entire face. The third piece of software, MeshMixer, is just a mesh editor and could easily be replaced with MeshLab or Blender.
[Oliver] still has a lot of work to do on the model of his skull – cleaning up the meshes, removing his mandible, and possibly plugging the top of his spinal column if he would ever want to print a really, really awesome mug. All the data is there, though, ready for digital manipulation before sending it off to be printed.
