Plastics: Photopolymers For 3D Printing And Beyond

December 21, 2021 by Dan Maloney 9 Comments

Chances are good that if you’ve done any 3D printing, it was of the standard fused deposition modeling variety. FDM is pretty simple stuff — get a bit of plastic filament hot enough, squeeze the molten goo out of a fine nozzle, control the position of the nozzle more or less precisely in three dimensions, and repeat for hours on end until your print is done. To the outsider it looks like magic, but to us it’s just another Saturday afternoon.

Resin printing is another thing altogether, and a lot closer to magic for most of us. The current crop of stereolithography printers just have a high-resolution LCD display between a UV light source and a build tank with a transparent bottom. Prints are built up layer by layer by flashing UV light patterns into the tank as a build plate slowly lifts it up from the resin, like some creature emerging from the primordial goo.

Of course it’s all just science, but if there is any magic in SLA printing, surely it’s in the resins used for it. Their nondescript brown plastic bottles and information-poor labels give little clue as to their ingredients, although their hydrocarbon reek and viscous, sticky texture are pretty good clues. Let’s take a look inside the resin bottle and find out what it is that makes the magic of SLA happen.

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Hackaday Links: December 19, 2021

December 19, 2021 by Dan Maloney 26 Comments

Key fobs as a service? Have we really gotten to that point? It would seem so, at least for Toyota, which is now requiring a subscription to use the company’s Remote Connect function. To be fair to Toyota, the Remote Connect system seems to do a bit more than the average key fob, with things like remote start and smartphone or smartwatch integration. It doesn’t appear that using the key fob for more mundane uses, like opening the doors, will be nerfed by this change. But if you want to warm up your car on a cold winter’s morn while you’re still in your jammies, then be prepared to cough up $8 a month or $80 a year on select 2018 and above models. Whether Toyota and other manufacturers get away with this nickel-and-dime stuff is up to the buyers, of course; if enough people opt out, maybe they’ll think of some other way to pad their bottom line. But since we’ve already seen heated seats as a service (last item), we suspect this is the shape of things to come, and that it will spread well beyond the car industry.

Speaking of cars, if you thought the chip shortage was over just because car dealer lots are filling back up, think again. Steve over at Big Mess o’ Wires reports that he’s having trouble sourcing chips for his vintage computer accessories. He includes a screenshot from Digi-Key showing zero stock on ATmega1284s. He also reports that the Lattice FPGA he uses for his Yellowstone universal disc controller is now unobtainium, where it had previously been easily sourced for about $5. He also has a pointed warning about some suppliers making it look like they have stock, only to send a “whoopsie” email after charging your credit card, or worse, telling you the price has increased over 400%. We suppose this was inevitable; there’s only so much fab capacity in the world, so eventually the fabs will switch over to producing whatever they can get paid the most for. And since car manufacturers have a lot more clout with suppliers than just about anyone else, it’s only natural for the shortages to shift down-market like this.

Do we finally have a “go” on James Webb? Maybe. The launch of the space telescope was originally scheduled for December 18 — well, OK, originally it was supposed to be in space in 2007, but let’s not go there — but a problem with a clamp caused unexpected vibrations in the $10 billion space observatory, resulting in inspections that pushed the launch back to the 22nd. That lasted for about a week, until the fueled and packaged spacecraft stopped sending data to launch controllers. The problem ended up being entirely relatable — a bad data cable — but resulted in the loss of two more days. JWST is now set to launch on Christmas Eve at 7:20 AM Eastern Standard Time, pending a readiness review on Tuesday morning. Fingers crossed that the long-awaited observatory has a safe 30-day trip to Lagrange point L2.

And finally, breathless tech journalists couldn’t wait to report this week that the world’s first warp bubble had been created. The paper was published by Dr. Harold “Sonny” White et al from the Limitless Space Institute, and claims to have discovered a “micro/nano-scale structure” that “predicts negative energy density distribution that closely matches requirements for the Alcubierre metric.” That last bit, the one about the Alcubierre metric, refers to the Alcubierre drive, which proposed a way to warp space-time and drive a ship at arbitrarily high speeds. But did this team actually create a warp bubble? It doesn’t seem so, at least according to one article we read. There’s also the problem of Dr. White’s previous claims of breaking the laws of physics with a reactionless EM drive. Scientific quibbling aside, there’s a sure-fire way of telling that no warp bubble was created — if there had been one, this would have happened.

Hackaday Podcast 149: Ballerina Bot Balances, Flexures Track Cat Food, PCB Goes Under The Knife, And An ATtiny Does The 555

December 17, 2021 by Dan Maloney 2 Comments

Newly ordained Hackaday editor-in-chief Elliot Williams and staff writer Dan Maloney jump behind the podcast mic to catch you up on all this week’s essential hacks. We’ll have a Bob Ross moment with an iPad, go to ridiculous lengths to avoid ordering a 555, and cook up a Wii in toaster. Need to make a VGA adapter from logic chips? Or perhaps you want to quantify the inner depths of human consciousness? Either way, we’ve got you covered.

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!

Direct download (55 MB)

Continue reading “Hackaday Podcast 149: Ballerina Bot Balances, Flexures Track Cat Food, PCB Goes Under The Knife, And An ATtiny Does The 555” →

Simple Mods Turn 3D Printer Into Electrochemical Metal Cutter

December 17, 2021 by Dan Maloney 30 Comments

We’re not aware of any authoritative metrics on such things, but it’s safe to say that the Ender 3 is among the most hackable commercial 3D printers. There’s just something about the machine that lends itself to hacks, most of which are obviously aimed at making it better at 3D printing. Some, though, are aimed in a totally different direction.

As proof of that, check out this Ender 3 modified for electrochemical machining. ECM is a machining process that uses electrolysis to remove metal from a workpiece. It’s somewhat related to electric discharge machining, but isn’t anywhere near as energetic. [Cooper Zurad] has been exploring ECM with his Ender, which he lightly modified by replacing the extruder with a hypodermic needle electrode. The electrode is connected to a small pump that circulates electrolyte from a bath on the build platform, while a power supply connects to the needle and the workpiece. As the tool traces over the workpiece, material is electrolytically removed.

The video below is a refinement of the basic ECM process, which [Cooper] dubs “wire ECM.” The tool is modified so that electrolyte flows down the outside of the needle, which allows it to enter the workpiece from the edge. Initial results are encouraging; the machine was able to cut through 6 mm thick stainless steel neatly and quickly. There does appear to be a bit of “flare” to the cut near the bottom of thicker stock, which we’d imagine might be mitigated with a faster electrolyte flow rate.

If you want to build your own Ender ECM, [Cooper] has graciously made the plans available for download, which is great since we’d love to see wire ECM take off. We’ve covered ECM before, but more for simpler etching jobs. Being able to silently and cleanly cut steel on the desktop would be a game-changer.

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A Nixie Clock, The Hard Way

December 15, 2021 by Dan Maloney 16 Comments

Notice: no vintage Hewlett Packard test equipment was harmed in the making of this overly complicated Nixie clock. In fact, if anything, the HP 5245L electronic counter came out better off than it went into the project.

HP 5245 hand-wired backplane — Beautiful hand-wired backplane in the HP 5245 counter.

We mention the fate of this instrument mainly because we’ve seen our fair share of cool-looking-old-thing-gutted-and-filled-with-Arduinos projects before, and while they can be interesting, there’s something deeply disturbing about losing another bit of our shared electronic heritage. To gut this device, which hails from the early 1960s and features some of the most beautiful point-to-point backplane wiring we’ve ever seen, would have been a tragedy, one that [Shahriar] wisely avoided.

After a bit of recapping and some power supply troubleshooting, the video below treats us to a tour of the Nixie-based beauty. It’s a wonderful piece, and still quite accurate after all these decades, although it did need a bit of calibration. Turning it into a clock non-destructively required adding a little bit of gear, though. Internally, [Shahriar] added a divide-by-ten card to allow the counter to use an external 10-MHz reference. Externally, an ERASynth++ programmable signal generator was used to send a signal to the counter from 0 Hz to 23,595.9 kHz, ramping up by 100 Hz every second.

The end result is the world’s most complicated 24-hour clock, which honestly wasn’t even the point of the build at all. It was to show off the glorious insides of the counter, introduce us to some cool new RF tools, and as always with [Shahriar]’s videos, to educate and inform. We’ve always enjoyed his wizardry, from his look into automotive radars to a million-dollar scope teardown, and this was another great project.

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PCB Microsurgery Puts The Bodges Inside The Board

December 14, 2021 by Dan Maloney 23 Comments

We all make mistakes, and there’s no shame in having to bodge a printed circuit board to fix a mistake. Most of us are content with cutting a trace or two with an Xacto or adding a bit of jumper wire to make the circuit work. Very few of us, however, will decide to literally do our bodges inside the PCB itself.

The story is that [Andrew Zonenberg] was asked to pitch in debugging some incredibly small PCBs for a prototype dev board that plugs directly into a USB jack. The six-layer boards are very dense, with a forest of blind vias. The Twitter thread details the debugging process, which ended up finding a blind via on layer two shorted to a power rail, and another via shorted to ground. It also has some beautiful shots of [Andrew]’s “mechanical tomography” method of visualizing layers by slowly grinding down the surface of the board.

[Andrew] has only tackled one of the bodges at the time of writing, but it has to be seen to be believed. It started with milling away the PCB to get access to the blind via using a ridiculously small end mill. The cavity [Andrew] milled ended up being only about 480 μm by 600 μm and only went partially through a 0.8-mm thick board, but it was enough to resolve the internal short and add an internal bodge to fix a trace that was damaged during milling. The cavity was then filled up with epoxy resin to stabilize the repair.

This kind of debugging and repair skill just boggles the mind. It reminds us a bit of these internal chip-soldering repairs, but taken to another level entirely. We can’t wait to see what the second repair looks like, and whether the prototype for this dev board can be salvaged.

Thanks to [esclear] for the heads up on this one.

Design For Test Hack Chat

December 13, 2021 by Dan Maloney 3 Comments

Join us on Wednesday, December 15 at noon Pacific for the Design for Test Hack Chat with Duncan Lowder!

If your project is at the breadboard phase, or even if you’ve moved to a PCB prototype, it’s pretty easy to know if it works. It either does what it’s supposed to do, or it doesn’t, and a few informal tests will probably tell you all you need to know. But once you scale up to production, the testing picture becomes quite different. How do you know you’re not shipping out a problem? And how do you make sure your testing process doesn’t become a bottleneck?

Answering questions like these can be difficult, which is why we’ve invited Duncan Lowder to come talk with us. He was a test lead at places like Glowforge and Sphero before founding FixturFab, where he’s working on ways to make hardware testing as easy as possible, no matter what scale you’re working at. We’ll learn all about how to make our designs easy to test right from the get-go and take the pain out of that bed of nails.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, December 15 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.