https://fldw.gitlab.io/ Recent content on Felix's Blog Hugo en-us Fri, 19 Jun 2026 00:00:00 +0000 https://fldw.gitlab.io/frabjous/ Fri, 19 Jun 2026 00:00:00 +0000 https://fldw.gitlab.io/frabjous/ Frabjous is a fantasy word introduced by Lewis Carroll, and repurposed in this context by George Hart to denote this dodecahedral star sculpture: https://www.georgehart.com/sculpture/frabjous.html The pattern I originally found was from here: https://www.thingiverse.com/thing:724 But it turned out to be hand-traced, so I redrew that in my CAD software with actual symmetry contraints and straight lines. Pattern to cut out # Here is a link to the svg. I think this repetition of the shape uses material quite efficiently, but there could be a better “tiling”. https://fldw.gitlab.io/start-polycarbonate/ Tue, 21 Apr 2026 00:00:00 +0000 https://fldw.gitlab.io/start-polycarbonate/ No one asked that question, so let me: What about polycarbonate? It’s a thermoplastic (✅ possible to 3D print), prints at typically 275°C (✅ reachable with typical 3D printers), is horribly hygroscopic (❌ humidity in a melting filament makes vapour bubbles), and can warp a lot (❌ enclosure required for any bigger pieces) The two red crosses can partially be circumvented though, so I gave it a try. Shredding # It all starts with shredding the polycarbonate into granules. https://fldw.gitlab.io/extruder-improvements/ Sun, 19 Apr 2026 00:00:00 +0000 https://fldw.gitlab.io/extruder-improvements/ As the extruder extrudes, the open-source nature of the machine gives me improvement ideas and easily allows to test them out. Some of the tests have a negative result, but those that have a positive result I try to add into the machine. The extruder has become a constant prototype, always with little changes “let me adjust that, before the next extrusion”. Here is a test, extruding with the fan from below, to see if the airflow direction can control the output diameter better from a certain angle (given turbulance from the other two fans as well). https://fldw.gitlab.io/yellow-strandbeest/ Wed, 08 Apr 2026 00:00:00 +0000 https://fldw.gitlab.io/yellow-strandbeest/ The Machine # The Strandbeest is a living sculpture designed and built by Theo Jansen. I find the leg mechanism mesmerising and was in the process of designing a walking robot using it. That project has somewhat stalled though, so I decided to take inspiration from another execution on the idea and 3D print it. Recycled # As a test of the recycled filament, only the yellow recycled PLA I produced recently was used. https://fldw.gitlab.io/led-lamp-1700k/ Sat, 04 Apr 2026 00:00:00 +0000 https://fldw.gitlab.io/led-lamp-1700k/ This is a little table lamp project around an LED chip I bought online, the colour is white but its colour temperature is a very warm 1700K: late sunset mood – almost orange. It has a power of max 10W and needs between 27 and 35V, going up for higher brightness. To power it and provide a brightness control, there is a DC-DC boost converter taking in 12V from a standard electronics power supply and stepping it up to the LED’s voltage. https://fldw.gitlab.io/modular-cube/ Fri, 13 Mar 2026 00:00:00 +0000 https://fldw.gitlab.io/modular-cube/ My mom had this great idea to use giftpaper for origami! This cube is assembled from twelve modules, one along each of its edges. All the holes mean less folding for me to do, and it still looks good. Inside view Try it yourself # The instructions are for a single module, twelve are needed in total. Start with square paper. Keep in mind that you are making a choice from which colour you have facing upwards at the start. https://fldw.gitlab.io/decoration-hiding-patterns/ Sun, 15 Feb 2026 00:00:00 +0000 https://fldw.gitlab.io/decoration-hiding-patterns/ The lasercutter made these little patterns out of wood, to hide the ugly drawer sliders. They can be used for any linear-style decorating. You could also use them for window borders plinth cornice/crown molding shelving decoration Try it yourself # Link to svg https://fldw.gitlab.io/stepper-motor-driver-test/ Fri, 13 Feb 2026 00:00:00 +0000 https://fldw.gitlab.io/stepper-motor-driver-test/ What is the purpose of this? Testing stepper motors: the circuit generates a blinking signal. The (purple PCB) driver then gets that blinking on its step pin. The idea is to connect a stepper motor to the driver, and the driver should start making the motor turn, thanks to the blinking signal fed to it. I just had some fun making the blinking part 3d soldered! As a simple testing setup, the direction pin is just shorted to ground and the step pin has some constant frequency signal with the intention of making the motor spin fast. https://fldw.gitlab.io/multilayer-happy-new-year/ Thu, 12 Feb 2026 00:00:00 +0000 https://fldw.gitlab.io/multilayer-happy-new-year/ “New Year”, yes yes it’s been just a little while since 2026 began, but it also took me some time to make this :) It started with this image I found online and wanted to adapt for lasercutting. The outlines can be traced automatically And then I spent some time arranging all the outlines into 7 different layers (the 8th layer is a full rectangle without any objects), with inside-outside objects also in the correct order. https://fldw.gitlab.io/links-inventory/ Wed, 11 Feb 2026 00:00:00 +0000 https://fldw.gitlab.io/links-inventory/ Extruding granules to filament # https://www.artme-3d.de/produkte/desktop-filament-extruder-mk3/ Lyman Extruder, inspiration for artme https://www.thingiverse.com/thing:1199870 and its firmware https://github.com/filipmu/Marlin-Mackerel https://support.3devo.com/filament-thickness-deviation-inconsistent-diameter Artme in practice: difficult to get all right at once, and highly dependent on input granules quality https://www.cnckitchen.com/blog/recycling-plastic-cutlery-into-3d-printing-filament Extruding granules for printing directly # https://mahor.xyz/ https://mahor.xyz/wiki/pellet-extruder-wiki/ https://ceadgroup.com/solutions/technology-components/ Not really consumer friendly in a 3D printer, such small scales amplify uneven extrusion problems. Industrial-grade high-volume 3d printers are the main focus of pellet extruders. https://fldw.gitlab.io/nosewarmer-2025/ Tue, 10 Feb 2026 00:00:00 +0000 https://fldw.gitlab.io/nosewarmer-2025/ In winter it gets quite cold, but I still cycle. To make that more comfortable, temperature control is important. Gloves and big shoes keep the hands and feet warm, but the nose is still exposed to a cold wind at all times. Putting cloth like a scarf or hood over it is a solution I tried before, but it doesn’t work well when breathing a lot. Also the cold bites through when outside temperatures go below 0°C and it almost doesn’t work below -10°C. https://fldw.gitlab.io/compound-5-tetrahedra/ Thu, 05 Feb 2026 00:00:00 +0000 https://fldw.gitlab.io/compound-5-tetrahedra/ This polyhedron is a glued-together set of five copies of a tetrahedron, going through each other ©Creative Commons wikimedia.org Pictured here with every tetrahedron in a different colour. I used the same mode of colouring for the paper model. Lasercutting # The svg design (linked below) fills one A4 piece of paper (or A3, A2; scale it up to your needs), so we need five A4 sheets of different colours. https://fldw.gitlab.io/catenary-coathanger/ Fri, 30 Jan 2026 00:00:00 +0000 https://fldw.gitlab.io/catenary-coathanger/ An idea to make nice coathangers: reusing some 5mm acrylic squares, lasercut the catenary curve shape out. Then, the acrylic can be heated up and progressively bent out of shape. 5mm seems thick enough for not breaking under a heavy load. The shape comes out flat after cutting. Notice the little oval cutouts at the ends of the catenary curve: they are there to prevent any cracks from propagating, and some negative space for material to bend into. https://fldw.gitlab.io/stellated-icosahedron/ Sun, 25 Jan 2026 00:00:00 +0000 https://fldw.gitlab.io/stellated-icosahedron/ Also known as small triambic icosahedron, this shape is built by putting simple 90° cube corners “on” every triangle of the icosahedron. ©Creative Commons wikimedia.org It is also called the first stellation of the icosahedron, because those added tips make it look a little like a star. There are also more stellations, which look progressively more pointy. Because the tips are cube corners, the Sonobe unit can be used Instructions for the basic Sonobe unit https://fldw.gitlab.io/great-dodecahedron/ Wed, 14 Jan 2026 00:00:00 +0000 https://fldw.gitlab.io/great-dodecahedron/ Motivation # The great dodecahedron is a simple enough polyhedron model for a multicolour result. It lends itself to an engaging colour choice: triangle faces of the same colour are in the same “slice-through” plane. Notice in the picture, the purple “sliced” plane. For the multiple colours to work, the flat pattern is first printed with a colour paper printer (2D). Then, it is lasercut. This step needs careful alignment with the pattern! https://fldw.gitlab.io/hot-air-balloon/ Tue, 09 Dec 2025 00:00:00 +0000 https://fldw.gitlab.io/hot-air-balloon/ While browsing lasercutting designs, I was impressed by this one: https://3axis.co/laser-cut-hot-air-balloon-3d-wooden-craft-kit-cdr-file/m1d643y7/ Which ended up being a little disappointing in terms of quality: it has a few inconsistencies, irregular colours and some parts are too many, others are missing. As-is, the design is not lasercuttable. Modifications # I improved on the following, which makes the svg file (link at the bottom) easier to lasercut and assemble: count how many parts are needed, remove the overflow. https://fldw.gitlab.io/recycling-2025-results/ Mon, 01 Dec 2025 01:00:01 +0000 https://fldw.gitlab.io/recycling-2025-results/ Gallery of some 3d prints from recycled filament Black and colour mix # 3D benchy, a benchmark for 3d printers. The black recycled PLA filament printed well. It also kept a black colour after being a mix of 40% black, 30% brown and 30% colourmix. The two smaller benchies look brown, but the original granules were purely a colourmix. The colours were all mixed thoroughly together during melting. The colour mix granules were wet during extrusion, but then I dried the resulting filament. https://fldw.gitlab.io/filament-extruder-2025-process/ Mon, 01 Dec 2025 00:30:01 +0000 https://fldw.gitlab.io/filament-extruder-2025-process/ Here is a description of my current process for recycling 3d printer filament waste back into (usable) 3d printer filament. I took these pictures over multiple runs, while still refining the process, so there will be a few different colours. For an evaluation and a look at the results, see here. Material # First, there are some prerequisites for successfully recycling filament for 3d printers. The main measure of success I use is how well the recycled filament can print on a normal printer with normal settings (just maybe temperature adjusted by +- 15C), especially compared to commercially offered filament. https://fldw.gitlab.io/star-trek-enterprise/ Mon, 10 Nov 2025 00:00:00 +0000 https://fldw.gitlab.io/star-trek-enterprise/ The model kit originally found on thingiverse: https://www.thingiverse.com/thing:1902315 Some modifications I added: rearranged parts to use the material more densely fuse bottom section coverings for sleeker assembly move some labels away for nicer end look Cutting Process # There are lines to only scar on the wood for aesthetic purposes, they are in blue in my design: these lines should not be cut trhough the full depth. The lasercutter also had issues making the text labels in blue, so I set those in black as polygons, for normal engraving. https://fldw.gitlab.io/glibc-repair/ Thu, 06 Nov 2025 00:00:00 +0000 https://fldw.gitlab.io/glibc-repair/ When trying to install a newer glibc, specifically 2.34, I got into this problem: I added the “locally installed” lib directory to the system paths this way chmod 0755 /root/ #yes yes that's bad. just to see if it _can_ work... echo '/root/glibc-2.34/lib' > /etc/ld.so.conf.d/new_libc.conf And reloaded ldconfig Then… Here is the history of this adventure copy pasted with only minial editing, and adding some of my thoughts along the way. https://fldw.gitlab.io/tealight-house/ Wed, 22 Oct 2025 00:00:00 +0000 https://fldw.gitlab.io/tealight-house/ I assembled this little “tealight” house, though more with a birdhouse in mind. The wood staining with dark adds some contrast, it was all plywood to start with. Because it’s all wood, do not put any kind of fire in there! Just use an artificial LED tealight… Try for yourself # Here is a link to the SVG file. https://fldw.gitlab.io/little-keiki/ Fri, 19 Sep 2025 00:00:00 +0000 https://fldw.gitlab.io/little-keiki/ I noticed this little bundle of leaves growing! This is a rare occurence, my phalaenopsis aren’t doing that usually. I’m suspecting it’s making an offshoot child (clone) plant, which for orchids is specifically called a keiki. Let’s see how much it grows, I plan on leaving it to grow until it has a few roots at least before separating. https://fldw.gitlab.io/boostconverters-currentcontrol/ Fri, 12 Sep 2025 00:00:00 +0000 https://fldw.gitlab.io/boostconverters-currentcontrol/ Motivation # The current electrical setup for the garden LED lights has DC to DC voltage boost converters. I always wanted to add brightness control, which is why I initially switched to those converters instead of connecting the LEDs directly to the 12v PSU at full brightness. That solution did allow for controlling the brightness, namely by using a screwdriver to turn a potentiometer which would increase or decrease the output voltage (when the boost converter is in CV mode). https://fldw.gitlab.io/led-lighting-2025-setup/ Wed, 09 Jul 2025 00:00:00 +0000 https://fldw.gitlab.io/led-lighting-2025-setup/ Garden # I have a little inside garden with about 2m2 of plants. The sunlight reaching them is very little, because the room only has a north facing window. Mostly for this reason but also for learning about electronics, I set up an artificial lighting system. It’s a set of LED lights that turn on every morning and off every evening. To also simulate the sun more closely, I programmed the automatic on/off virtual day to follow a lengthening/shortening over the year to make a solstice/equinox effect. https://fldw.gitlab.io/tricycle-lasercut/ Tue, 01 Jul 2025 00:00:00 +0000 https://fldw.gitlab.io/tricycle-lasercut/ I found this lasercutter svg model online for free, and was intrigued by the planetary gears! It uses them instead of a chain (which would be difficult to lasercut) and solves that in an elegant way. Despite the lack of instructions, it can be put together following the single picture and guessing. Also, this is near to fully functional: the pedals can rotate, and they drive the front wheel. The back wheels are also free to rotate. https://fldw.gitlab.io/coffee-roaster-cylinder/ Thu, 08 May 2025 00:00:00 +0000 https://fldw.gitlab.io/coffee-roaster-cylinder/ I’ve been roasting coffee beans for my own consumption for a few years by now, and I wanted something better than doing it in the pan. Here is a picture of the beans roasting in my oven. They are rotated in a cylinder for uniform roasting. Previous attempts at roasting in the oven, with the beans just spread out flat, did roast but quite badly: beans at the top were over-roasted and almost burned black, whereas beans below were under-roasted. https://fldw.gitlab.io/filament-extruder-build/ Sun, 12 Jan 2025 00:00:00 +0000 https://fldw.gitlab.io/filament-extruder-build/ What is an extruder? # Artme MK3 filament extruder I assembled This filament extruder is a machine that produces plastic filament, specifically for use by 3d printers. To do this, it melts granules and pushes on them to produce pressure. Plastic is a polymer that does not have a precise melting point, rather a melting range. When the granules are under pressure and heated, the temperature does not need to be as high to get them liquid. https://fldw.gitlab.io/contact/ Mon, 01 Jan 0001 00:00:00 +0000 https://fldw.gitlab.io/contact/