Author Archives: pappp

Pismo Powerbook

Picture of a running Pismo Powerbook, showing the "About this Mac" page and list of installed Applications

I’ve wanted one of the curvy bronze-keyboard G3 Powerbooks since they were new – I’ve always been kind of taken by the design language (half business, half iBook). I got to play with a university-owned Wallstreet for a while as a kid, so I remember them beyond looking in catalogs, and uh… I really like a bunch of classic Mac games and want a convenient late-classic machine to run them natively, because a few are glitchy in emulation.

So, I occasionally lowball bid promising auctions when one comes up somewhere. A few months ago (in late February) there were a succession of them on ShopGoodwill, and I tossed a $50 max bid on a Pismo in the 500MHz/128MB/12GB/DVD configuration in unknown electrical and OK but not perfect cosmetic condition. And, surprisingly, won. It ended up being about $67 with shipping/handling/tax/etc. Since working condition examples tend to be around $200, this seems like a decent deal. It survived the typically awful shipping, and, in long form below, it turned out to be a good buy.

Continue reading
Posted in Computers, DIY, Electronics, Objects | Leave a comment

US, China agree to roll back tariffs – but only for 90 days

Source: The Register

Article note: Oh good, sanity has prevailed before things got _really_ bad, and all we got was a market crash, a massive weakening of US foreign interests by damaging the dollar as a reserve currency, and a few weeks of crony capitalism exception/extortion shenanigans. I suppose now Donnie Dipshit is going to announce what a brilliant and powerful negotiator he is and the cult members will believe him.

IT projects may remain in limbo due to deal being far from final, but markets are up, so Trump'll declare a win

world war fee  The impending disaster of trade-freezing tariffs on Chinese imports to the US has been averted, but like a Chinese cargo ship anchored off the coast of California, it's not gone entirely.…

Posted in News | Leave a comment

US Copyright Office found AI companies sometimes breach copyright. Next day its boss was fired

Source: The Register

Article note: I'm very much a copyright minimalist, I think the terms should be shorter and private use exceptions broader... and even I think the mass infringement of recent works for commercial use by the AI douches is gross.

Some see an action to benefit Elon. The White House sees an agency obsessed with DEI

The head of the US Copyright Office has reportedly been fired, the day after agency concluded that builders of AI models use of copyrighted material went beyond existing doctrines of fair use.…

Posted in News | Leave a comment

Experiments in Filament Drying

I’ve had a few projects recently that needed 3D printed parts, went to use a roll of black eSun PLA+ that I accidentally left out in my basement for some time, and it produced the telltale dull, rough, stringy, gappy print quality of hydrated filament.
Since I have some energy for projects right now, I decided it was finally time to get a filament dehydrator setup.

A part ruined by wet filament
Pretty sure PLA printed to a glass bed shouldn’t look like this…

I went reading up about filament dehydration. The purpose-made filament dryers mostly seem to have a problem with actually removing moisture, most of them are dry boxes with no exhaust path, and the liberated water vapor has to go somewhere. Many seem to rely on instructions for the user to periodically open the lid during drying (which is …not automated), and a few contain a large amount of desiccant that will be more-hydrophilic than most filaments at drying temperatures, then itself require dehydration. Bambu seems to be doing basically the right thing with the AMS2 Pro and it’s automatic exhaust valve, but I’m not in the Bambu ecosystem and not looking to spend that kind of money.

So, instead, I looked at the DIY options. There are a variety of clever schemes with PID controllers and heating elements… but lot of folks seem to just repurpose inexpensive food dehydrators, and I went with a variation on that plan.

I picked up a $40 Elite Gourmet EFD770WD dehydrator; I paid a few extra bucks for a model with a digital thermostat/timer. It gets me a heater, a blower, and thermostatic control in a package that is at least theoretically safe for consumer use, which is really all that is called for.
There are many directions on the internet for cutting the grilles out of several trays on this style of dehydrator to make a spool-sized cavity, and many designs for large, elaborate, and almost inevitably multi-part printable extension tubes, which must be printed in a filament still rigid at the highest drying temperature you expect to need. The former seems wasteful and the latter seems like a tedious hassle.

A little foamcore and tape to make a suitable cavity.

I did something much lazier and made a tube out of foamcore. Just bent it using the little tabs for aligning the trays and taped. Mine is two pieces because none of my scrap pieces were quite large enough to do it in one.
The foamcore is slightly insulating which seems like a minor feature, and this method isn’t many hours of printing or destructive, which is a major feature.
I also saw several folks modifying a 3.5gal or 5gal paint bucket with a diameter around 12.5″, and I may try that in the future as a more polished solution, but didn’t have a suitable empty on hand.

This particular dehydrator only lets you pick specific temperatures, but 115 and 125F are options right to either end of the suggested range for drying PLA variants. As for effectiveness, the main subject roll of black eSun PLA+ that sat out for a couple months, whose behavior is pictured above, went in for 8 hours at 115F, and initial results were really promising.

Close-up comparison of a part printed in very hydrated PLA and the same PLA after a cycle in a dryer
The first experiment looked really promising; Same printer, same gcode, top print before drying, bottom print after 8H@115F. Almost all defects were gone from the first layer.

There were still some hydration-looking defects in areas (and the thermocouple I had shoved in through one of the lid slots of the dehydrator as a safety was reading a little low), so I gave it another 8 hours at 125F. And the results didn’t really change, but there was no obvious degradation. It has a dead spool producing parts that are usable if a little textured, which is worthwhile.

Sample prints of the same filament under additional levels of drying.
Similar parts printed wet, dried for 8 hours at 115F, and dried an additional 8 hours at 125F. It’s unclear if the subsequent/hotter drying offers any significant benefit.

PLA+ is always a bit of a mystery material, I’ve generally supposed that much of it is doped with a couple percent PBT, but the relevant eSun PLA+ MSDS just shows 2-4% calcium carbonate (which apparently just provides nucleation sites to improve the crystallization) and 2-5% “other,” (likely pigment). CaCO3 isn’t very soluble in water, but who knows how it moved around or altered crystallization or whatnot during the wet-dry cycle. I ran some Inland “Egyptian Blue” regular PLA that had sat out in the basement for a while through a similar 8h@125F cycle and it did seem to reduce the surface irregularities (pips, especially on corners) between the previous and next part I printed in it, but not in such a dramatic way.

From a somewhat-amateur reading of the relevant literature, it seems like not all the hydration induced changes should be reversible. The most relevant thing I could find was Beyond Biodegradability of Poly(lactic acid): Physical and Chemical Stability in Humid Environments (2017) which looks at degradation due to liquid and vapor phase water infiltration, and found pretty substantial chemical changes especially from vapor at higher temperature.
The literature in general is a little spotty, there are more liquid phase studies (eg. ref), but studies like the earlier one comparing liquid and vapor phase water infiltration indicate they aren’t entirely comparable. The literature on drying is “thin,” and the relevant Internet content is thoroughly astroturfed by vendors trying to sell you gadgets (which is becoming a real problem in the 3D printing market in general; good luck finding un-sponsored information about anything). I’m sure some of the commercial (bio)plastic manufacturers/processors have detailed internal documentation, but they aren’t sharing.

In the same order as they dryer, I picked up some indicating desiccant packs to improve my ability to monitor and dry filament in bags. I’m so distrustful of Amazon junk now, I stuck one in the bathroom to absorb shower steam to see what the indicator hydration process looked like, and it is slowly turning pink after being repeatedly exposed to shower steam. Hopefully storing filament with known-dry desiccant will help keep it from going bad – at least as long as I continue avoiding any of the truly hydrophilic materials like Nylon that require special handling.

All in all: Hydration is absolutely a problem for PLA and adjacent materials, drying is imperfect but effective, slightly modified food dehydrators that exhaust the vapor do a fine job, and keeping material dry is better than trying to dry it.

Posted in DIY, General, Objects | Leave a comment

Testing different temperature sensors for a DIY thermostat

Source: adafruit industries blog

Article note: Super useful for putting together effective devices from questionable China export parts. Would love to have similar results for a range of sensing devices.

Oleg Tarasov has tested six temperature sensors for use in a thermostat project.

A crucial step towards my goal of individual room temperature control is to be able to measure current room temperature with precision and minimum amount of lag.

Important note: all of my sensors were sourced from China, and most of them from AliExpress. I did not get my sensors from official distributors, so there is a real possibility that all sensors I tested were unreliable knock-offs.

I thought that I’ll just slap together a couple of random sensors, write some code and be done with my per-room thermostats project. Instead, I’m doing this on and off for almost half a year and get a occasional raised eyebrow from my wife while dipping weird-looking stuff in ice water � But it’s actually fun and I learn a lot of stuff in the process, and isn’t it this the true goal?

See the testing process in the post here.

Posted in News | Leave a comment

Echoes of Wisdom is Merely OK

I played The Legend of Zelda: Echoes of Wisdom (as a distraction to avoid losing my mind reading the last giant batch of lab reports for the semester) since I finally found a copy for a vaguely reasonable price a few weeks ago, and will play anything from the franchise. It’s… OK. Thoughts:

  • The main echo gimmick is novel and mostly positive;
    • it’s narratively a neat way to have the player character (who is Zelda) not get their hands dirty
    • it’s pretty clear when you can learn something, and which things on screen are your echoes
    • it’s fun to try applying different echoes to situations
    • …but it involves a ton of menuing, which their attempts to make affordances for don’t quite cover up
    • and there are quite a few points where it’s aggravating to get an echo to do what you clearly need it to
  • The game is pretty short. A bit unsatisfyingly so.
  • The vast majority of puzzles are highly telegraphed and fairly trivial (most are just interesting enough to be satisfying) and a few are “go look up what obnoxious detail makes the obvious solution frustrating to execute”
  • The minor characters and side quests are not very interesting, which is something Zelda games are usually better at
    • I went in and played a bunch of side content after I beat the game, just looking for interest.
  • Several of the mechanics just…aren’t very useful:
    • If you can find a safe spot, you can always heal with a bed, so smoothies matter once for cold resistance and otherwise only if you need to heal during a boss because you did something dumb.
    • Once you have clouds, the other platforming-related echoes are largely irrelevant.
    • I… didn’t even bother with Dampe and the automatons until I went back to mop up stuff I missed after I finished. It feels more like an alternate pitch to the echo system that they didn’t quite let go of.

It’s not a bad game, but don’t pay full price.
Given that the 3D Zeldas for the Switch (BoTW and ToTK) were excellent, do those first if you haven’t. And if you specifically want a 2D Zelda-like and you haven’t played Tunic (which is a 2D Zelda influenced game whose magenta otherworldly corruption feels like it might have fed back into the franchise with this one), do that first, it’s more interesting.

Posted in Entertainment, General | Leave a comment

Signal clone used by Trump official stops operations after report it was hacked

Source: Ars Technica

Article note: It's an absolute onion of incompetence. Doing high-net shit over commercial software on the public internet. Getting caught doing it by adding the most wrong people possible to your chats, and using your public phone numbers, and letting the media photograph the behavior. Picking the most secure option... but using a version hacked by an Israeli spyware vendor to allow retention, so you can pretend to comply with records acts. Getting hacked because said Israeli spyware vendor who appears to have hired a mediocre college student to do the modifications. It's honestly hard to imaging someone fucking up harder.

A messaging service used by former National Security Advisor Mike Waltz has temporarily shut down while the company investigates an apparent hack. The messaging app is used to access and archive Signal messages but is not made by Signal itself.

404 Media reported yesterday that a hacker stole data "from TeleMessage, an obscure Israeli company that sells modified versions of Signal and other messaging apps to the US government to archive messages." 404 Media interviewed the hacker and reported that the data stolen "contains the contents of some direct messages and group chats sent using [TeleMessage's] Signal clone, as well as modified versions of WhatsApp, Telegram, and WeChat."

TeleMessage is based in Israel and was acquired in February 2024 by Smarsh, a company headquartered in Portland, Oregon. Smarsh provided a statement to Ars today saying it has temporarily shut down all TeleMessage services.

Read full article

Comments

Posted in News | Leave a comment

Matrix-vector multiplication implemented in off-the-shelf DRAM for Low-Bit LLMs

Source: Hacker News

Article note: This is really fucking cool. It's an quite old idea, put together effectively by misusing fairly modern commodity hardware, by applying out-of-spec behavior determined by security research.
Comments
Posted in News | Leave a comment

Design for 3D-Printing

Source: Hacker News

Article note: This is a thing folks I know have been hammering on for years and I agree. Like all manufacturing technologies, 3D printers aren't replicators, there are at least heuristics for what will fabricate well. It's not too hard to enumerate heuristics, but it turns out to be extremely hard to automate or even hint effectively. I'm interested to see in the comments that no one else has had much luck automating 3D printing DFM.
Comments
Posted in News | Leave a comment

Vygotsky’s Zone of Proximal Development

Source: Hacker News

Article note: This is a big part of how I design coursework (and _that_ is one of the ways that my having sought out some formal instructional design training differentiates me from many faculty). The hard part is figuring out how to design exercises that have fronts in the ZPD for a range of students without inappropriately scraping anyone off.
Comments
Posted in News | Leave a comment