Nylon-Like TPU Filament: Testing CC3D’s 72D TPU

July 22, 2025 by 6 Comments

Another entry in the world of interesting FDM filaments comes courtesy of CC3D with their 72D TPU filament, with [Dr. Igor Gaspar] putting it to the test in his recent video. The use of the Shore hardness D scale rather than the typical A scale is a strong indication that something is different about this TPU. The manufacturer claims ‘nylon-like’ performance, which should give this TPU filament much more hardness and resistance to abrasion. The questions are whether this filament lives up to these promises, and whether it is at all fun to print with.

The CC3D 72D TPU filament used to print a bicycle's handlebar. (Credit: My Tech Fun, YouTube)
The CC3D 72D TPU filament used to print a bicycle’s handlebar grips. (Credit: My Tech Fun, YouTube)

TPU is of course highly hydrophilic, so keeping the filament away from moisture is essential. Printing temperature is listed on the spool as 225 – 245°C, and the filament is very bendable but not stretchable. For the testing a Bambu Lab X-1 Carbon was used, with the filament directly loaded from the filament dryer. After an overnight print session resulted in spaghetti due to warping, it was found that generic TPU settings  at 240ºC with some more nylon-specific tweaks seemed to give the best results, with other FDM printers also working well that way.

The comparison was against Bambu Lab’s 68D TPU for AMS. Most noticeable is that the 72D TPU easily suffers permanent deformation, while being much more wear resistant than e.g. PLA. That said, it does indeed seem to perform more like polyamide filaments, making it perhaps an interesting alternative there. Although there’s some confusion about whether this TPU filament has polyamide added to it, it seems to be pure TPU, just like the Bambu Lab 68D filament.

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A cylindrical red furnace is in the center of the image. To the left of it is a black power supply. A stand is in front of the furnace, with an arm extending over the furnace. To the right of the furnace, a pair of green-handled crucible tongs sit on an aluminium pan.

The Hall-Héroult Process On A Home Scale

July 22, 2025 by 8 Comments

Although Charles Hall conducted his first successful run of the Hall-Héroult aluminium smelting process in the woodshed behind his house, it has ever since remained mostly out of reach of home chemists. It does involve electrolysis at temperatures above 1000 ℃, and can involve some frighteningly toxic chemicals, but as [Maurycy Z] demonstrates, an amateur can now perform it a bit more conveniently than Hall could.

[Maurycy] started by finding a natural source of aluminium, in this case aluminosilicate clay. He washed the clay and soaked it in warm hydrochloric acid for two days to extract the aluminium as a chloride. This also extracted quite a bit of iron, so [Maurycy] added sodium hydroxide to the solution until both aluminium and iron precipitated as hydroxides, added more sodium hydroxide until the aluminium hydroxide redissolved, filtered the solution to remove iron hydroxide, and finally added hydrochloric acid to the solution to precipitate aluminium hydroxide. He heated the aluminium hydroxide to about 800 ℃ to decompose it into the alumina, the starting material for electrolysis.

To turn this into aluminium metal, [Maurycy] used molten salt electrolysis. Alumina melts at a much higher temperature than [Maurycy]’s furnace could reach, so he used cryolite as a flux. He mixed this with his alumina and used an electric furnace to melt it in a graphite crucible. He used the crucible itself as the cathode, and a graphite rod as an anode. He does warn that this process can produce small amounts of hydrogen fluoride and fluorocarbons, so that “doing the electrolysis without ventilation is a great way to poison yourself in new and exciting ways.” The first run didn’t produce anything, but on a second attempt with a larger anode, 20 minutes of electrolysis produced 0.29 grams of aluminium metal.

[Maurycy]’s process follows the industrial Hall-Héroult process quite closely, though he does use a different procedure to purify his raw materials. If you aren’t interested in smelting aluminium, you can still cast it with a microwave oven.

Video Tape Hides Video Player

July 22, 2025 by 16 Comments

While it might not be accurate to say VHS is dead, it’s certainly not a lively format. It continues on in undeath thanks to dedicated collectors and hobbyists, some of whom may be tempted to lynch Reddit user [CommonKingfisher] for embedding a video player inside a VHS tape.

Miniaturization in action. The video player probably cost about the same as the original VHS when you account for inflation.

The hack started with a promotional video card via Ali Express, which is a cheap enough way to get a tiny LCD player MP4 playing micro. As you can see, there was plenty of room in the tape for the guts of this. The tape path is obviously blocked, so the tape is not playable in this format. [CommonKingfisher] claims the hack is “reversible” but since he cut a window for the LCD out of the casing of the cassette, that’s going to be pretty hard to undo. On the other hand, the ultrasonic cutter he used did make a very clean cut, and that would help with reversibility.

The fact that the thing is activated by a magnetic sensor makes us worry for the data on that tape, too, whether or not the speaker is a peizo. Ultimately it doesn’t really matter; in no universe was this tape the last surviving copy of “The Matrix”, and it’s a lot more likely this self-playing “tape” gets watched than the VHS was going to be. You can watch it yourself in the demo video embedded below.

VHS nostalgia around here usually involves replicating the tape experience, rather than repurposing the tape. We’re grateful to [George Graves] for the tip. Tips of all sorts are welcome on our friendly neighborhood tips line.

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2025 One Hertz Challenge: A 555, But Not As We Know It

July 22, 2025 by 2 Comments

We did explicitly ask for projects that use a 555 timer for the One Hertz Challenge, but we weren’t expecting the 555 to be the project. Yet, here we are, with [matt venn]’s Open Source 1Hz Blinky, that blinks a light with a 555 timer… but not one you’d get from Digikey. 

Hooking a 555 to blink an LED at one hertz is a bog-simple, first-electronics-project type of exercise, unless you have to make the 555 first. Rather than go big, as we have seen before, [matt venn] goes very small, with a 555 implemented on a tiny sliver of Tiny Tapeout 6.

We’ve covered projects using that tapeout before, but in case you missed it, Tiny Tapeout gives space to anyone to produce ASICs on custom silicon using an open Process Design Kit, and we have [matt venn] to thank for it. The Tiny Tapeout implementation of the 555 was actually designed by [Vincent Fusco].

Of course wiring it up is a bit more complicated than dropping in a 555 timer to the circuit: the Tiny Tapeout ASIC must be configured to use that specific project using its web interface.  There’s a demo video embedded below, with some info about the project– it’s not just a blinking LED, so it’s worth seeing. The output isn’t exactly One Hertz, so it might not get the nod in the Timelord category, but it’s going to be a very strong competitor for other 555-based projects– of which we could really use more, hint-hint. You’ve got until August 19th, if you think you can use a 555 to do something more interesting than blink an LED.

2025 Hackaday One Hertz Challenge

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2025 One-Hertz Challenge: Pokémon Alarm Clock Tells You It’s Time To Build The Very Best

July 22, 2025 by 3 Comments

We’ve all felt the frustration of cheap consumer electronics — especially when they aren’t actually cheap. How many of us have said “Who designed this crap? I could do better with an Arduino!” while resisting the urge to drop that new smart doorbell in the garbage disposal?

It’s an all-too familiar thought, and when it passed through [Mathieu]’s head while he was resetting the time and changing the batteries in his son’s power-hungry Pokémon alarm clock for the umpteenth time, he decided to do something about it.

The only real design requirement, imposed by [Mathieu]’s son, was that the clock’s original shell remained. Everything else, including the the controller and “antique” LCD could go. He ripped out the internals and installed an ESP32, allowing the clock to automatically sync to network time in the event of power loss. The old-school LCD was replaced with a modern, full-color TFT LCD which he scored on AliExpress for a couple of Euros.

Rather than just showing the time, the new display sports some beautiful pixel art by Woostarpixels, which [Mathieu] customized to have day and nighttime versions, even including the correct moon phase. He really packed as much into the ESP32 as possible, using 99.6% of its onboard 4 MB of flash. Code is on GitHub for the curious. All in all, the project is a multidisciplinary work of art, and it looks well-built enough to be enjoyed for years to come.

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The Epochalypse: It’s Y2K, But 38 Years Later

July 22, 2025 by 41 Comments

Picture this: it’s January 19th, 2038, at exactly 03:14:07 UTC. Somewhere in a data center, a Unix system quietly ticks over its internal clock counter one more time. But instead of moving forward to 03:14:08, something strange happens. The system suddenly thinks it’s December 13th, 1901. Chaos ensues.

Welcome to the Year 2038 problem. It goes by a number of other fun names—the Unix Millennium Bug, the Epochalypse, or Y2K38. It’s another example of a fundamental computing limit that requires major human intervention to fix. 

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USB-C-ing All The Things

July 22, 2025 by 49 Comments

Wall warts. Plug mounted power supplies that turn mains voltage into low voltage DC on a barrel jack to power a piece of equipment. We’ve all got a load of them for our various devices, most of us to the extent that it becomes annoying. [Mikeselectricstuff] has the solution, in the shape of a USB-C PD power supply designed to replace a barrel jack socket on a PCB.

The video below provides a comprehensive introduction to the topic before diving into the design. The chip in question is the CH224K, and he goes into detail on ordering the boards for yourself. As the design files are freely available, we wouldn’t be surprised if they start turning up from the usual suppliers before too long.

We like this project and we can see that it would be useful, after all it’s easy to end up in wall wart hell. We’ve remarked before that USB-C PD is a new technology done right, and this is the perfect demonstration of its potential.

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