Open_ERV

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Are you stressed out about masking and being air-aware when it seems like nobody else cares? Or is having Long COVID stressing you out? Join us and @AirSupportBox on Sunday, July 26 for a discussion with Amy Stewart, LCSW, about managing stress with being air-aware.

Ok so the big printer turns out to use a ribbon cable of unusually large wire gauge, they send all the power for the hot end and stepper motor down the ribbon cable. There is nowhere I can get this part. Not mcmaster, any of the electronic supply places (newark, mouser, digikey etc). *don't use parts that cannot be replaced in your design*. However I can circumvent the broken wires easily enough. When the rest of the cable eventually fails, I will probably have to cut the ends off of the cable and solder 30 individual wires back on, to replace whatever else breaks. Actually only 20 of the wires are used, but it's not practical to know which ones, there is no source code for the machine. Never ever buy tronxy.

@Makr3D it was indeed labelled pc-cf.

@open_erv Amazon switching the listing from PC-CF to PETG-CF is the bigger red flag here. Those materials should not be interchangeable in the product description. Did the spool label or box show a specific polymer and drying profile?

Well, I tried CF reinforced polycarbonate filament today. It may be this particular brand/filament is no good and the technology is ok. But this was completely useless. Absurdly, comically fragile. I think probably it's this particular product, it's completely useless. So beware when buying PC-CF, I guess. I'll have to try a name brand like prusament or polymaker perhaps. This was the stuff that was no good: edit: my order history clearly shows it was advertised as polycarbonate -cf, now this one shows it was petg-cf at that listing. Amazon switched the listings. So definitely sketchy company. Better just try again with a reliable company.

I was just about to order the 25 custom boxes, they are turning out to be $23 each after tax.... and I noticed they shaved a third of an inch off the dimensions. WTF? If it's custom anyway? That's the extra space I needed for packing material to help ensure it doesn't get broken... facepalm. Tolerances are not that tight but you can't be changing things by a third of an inch on two sides without telling me... Fortunately I caught it before I paid $575 and they landed me with a ton of boxes slightly the wrong size rolleyes.

Nice! I think the self tapping screws, or the machine screws right into the plastic, might last a surprisingly long time. In my experience they tend to, the plastic squishes around but rarely actually leaves the hole. I can also use a slightly longer screw if the old one doesn't grab anymore, usually. My phone doesn't have a barometer, but I have an sps30 sensor I could use... In the past, I used a similar approach, using slices of the tw4 heat exchanger in a pipe as the resistance elements, and the pressure sensor after the flow restrictor. They can be stacked to form greater or lesser resistance. That's a hassle to print though. Again the only purpose was to compare fans, in that case I also got flow measurements with a hot wire anemometer. Yesterday I was thinking of how I might do this kind of thing, and I think I might try a paddle with a weight, and suspended on a wire. The paddle in the airflow path, and then three different flow restrictors. The air would come through the flow restrictor and hit the paddle. It would not be able to measure actual static pressure. The position of the paddle would rotate until equilibrium was achieved with the air hitting it. It might bounce around, though. The whole thing would have to be level. I like this kind of thing because it depends only on weights and airflow, not for cost but for the natural accuracy and repeatability that can bring. I tried using inclined manometers which similarly draw more directly from natural phenomena, but they did not work out well, for pressure measurement n this context. The problem with a non inclined manometer is that the fluid is too dense, you have a very hard time measuring only a couple pascals, and repeatably. The inclined manometer is better but has to be level, and the hysteresis caused by the meniscus is a real problem. In the end I switched to the sps30 for pressure, and it's actually a flow measurement device in disguise. It has a tiny hole in it and measures the airflow through the hole, using the same principles as a hot wire anemometer, then computes pressure. But the sps30 is not needed for this kind of thing. Indeed, since the only challenge is to match fans, I would not bother with calibration, you can just measure a bunch of fans and match them from that. After my exploration of this kind of thing for some time, my favorite method to try in the future is the use of a camera and some kind of floating or high drag to weight ratio object, perhaps a bit of dryer lint or some fluffy seed stuff. I would print a rig to hold the camera, and focus the camera at a fixed point, hold a ruler up to determine the mm per pixel (the ruler can be removed to not affect airflow), and then at the same distance from the camera, release the fluffy stuff with some tweezers. Frame by frame analysis could be used just by eye to determine m/s. I found some stuff for the phone that does this, called frameskip, but you could just transfer it to the computer, kind of nice to be able to do it on your phone. Then you would need various flow restrictors with known properties. I found it to be awkward and not as easy as I thought, but I think it has potential for more precise measurements, perhaps calibrating this kind of thing with a complicated but low cost procedure. It could also be used to measure the airflow at the intake of the actual air purifier, perhaps. I like this more than a hot wire anemometer even, because it's pretty closely tied to things we know are highly accurate, the timing of the phone and the camera (and the yardstick/ruler/measuring tape). I made a $1 anemometer, which is shared in the BQAP github repository (requires a pico or similar to read it), which appears to have good repeatability and precision in the 0.1 m/s range, and I figured out a way to calibrate it. I swing it on an arm of known length at known speed through still air. I haven't done it with that anemometer yet, but I used the method to validate an off the shelf hot wire (thermistor) anemometer and it went well.

@eddericu @NukitToBeSure I also talked to Northbox about splicing in the anemometer and wifi control/monitoring box into one of their air cleaners. We never got around to it.

@NukitToBeSure I think having pressure sensors could then help automate that live CADR estimation. Answers a lot: are the air cleaners on? Are they working as intended? (Maybe one of the PC fans stopped working) Are we reaching standards like ASHRAE 241? Etc…

Oh, I think I can approximate filter cube/box CADR with the same trick🤔

The BQAP had this. I developed a super cheap anemometer. It was very slow to respond but with good repeatability. If you knew the CADR when the filters are new, you are good. I never got around to calibrating the anemometer. This would require simply attaching it to a moving arm and moving it at a known speed in otherwise still air. I built the apparatus to do it, though. However filter efficiency is also a factor, not just airflow. They both change with time. A device which emitted a small amount of particles, with an ultrasonic fog generator, for instance, and measured the exponential decline, could be more effective, and it would measure net CADR for the whole room from all sources. Remember we considered this ages ago. I think it is still the best idea, but it would be $100 instead of $1 that my anemometer costs.

@VitalikButerin I'm so glad you guys are on the case because I hardly understand most of this stuff. I do try to keep up but so much to do all the time...

One thing I find striking in the discourse between AI 2040 and its detractors is that the two seem to be locked in to totally incompatible worldviews of how fast and how much of a big deal AI progress is: * In AI 2040, every scenario sees superintelligence of some kind emerging by 2040, unless a herculean effort is made to completely stop it * Detractors say things like "AI 2040 is naive about human coordination ability and a threat to freedom", but don't seem to see any naivety in assuming that the ASI transition will just go well by default, don't seem to see ASI itself as a massive power concentrator risk, and don't seem to feel fear of humanity's "hard power" dropping to zero if ASIs can do literally every task better than we can. This stance makes total sense in a "AI is normal technology" world, zero sense in a world where superintelligence is possible by 2030 and almost guaranteed by 2040 I think my beliefs are: - If I was confident that (present-day-style) AI is normal technology, I would be in the detractor camp - If I was confident that superintelligence is coming in 2030 by default, I would be closer to the AI 2040 camp - it's naive, but every other option is naive squared? But my problem is that I feel great uncertainty and have no idea which of the two worlds (or some other third thing) we're living in? Hence why I continue to be open-minded about slowdowns/pauses, but also I feel very uncomfortable with the "open source bad, the good outcome is the one where our guys have controlling global dominance" push coming from some major AI companies and intellectuals - in a "normal" world that's the sort of thing that triggers every political alarm bell at the same time. A big reason why I have been advocating and trying my best to support the d/acc platform (rapid up-skilling in formal verification, cryptography, secure and open hardware, pandemic resistance and other defensive biotech, food and basic resource security, public epistemics, non-power-concentrating versions of physical security) is that these things are clearly worth doing in both worlds. The 2040 plan is already much more open source friendly (even mandating it! yay). It also includes "mutually assured compute destruction" ideas which (if they work) effectively give one of 2-5 actors the ability to trigger a global compute winter - as opposed to giving 1-5 actors the ability to selectively disenfranchise people they consider baddies while exempting themselves. This is also a big improvement. So I can see the earnest attempts to improve along the dimensions detractors criticize on ("does this concentrate power in big AI labs and superpower governments?"), and I appreciate this. I think many people don't appreciate enough the differences between different "kinds" of pause buttons, and how some concentrate power far more than others. Probably we can think harder and improve even more here. But on the "slowdown/pause or not" topic, there isn't a magic "escape the tradeoff" button. The Hansonian in me says: the winning deal is a deal which, from the perspective of both sides' present-day beliefs and knowledge, both sides would accept, though for different reasons. If the crux is AI progress speed, then identify a set of pre-agreed triggers for "okay, serious shit is happening" [super-pandemics? >25% unemployment? something involving slaughterbots?], and pre-agree that we become much more open-minded to the slowdown or pause thing if enough triggers come to pass within some timeframe. 2040 detractors (who clearly implicitly think that we'll see amazing speedup of progress from AI but think that what I call the "serious shit" category is overhyped) will accept expecting that the triggers don't come to pass, and AI worriers will accept expecting that they will. Pre-agreeing on the specific triggers means that once the triggers either hit or don't hit, there is stronger legitimacy around the idea that one side's worldview turned out more correct and we should be more inclined toward their program. If I were @elonmusk (or zuck, or...) I would re-tool twitter much more heavily into being a platform for helping to identify and make these kinds of grand win-win deals, so that we can bypass big-country governments and big-company CEOs and big nonprofit intellectuals and give more people a voice in the discussion. It's possibly one of the best things that social media _could_ do for humanity if it wanted to. But again, maybe this is also naive. Actually, probably it's naive. But currently, I see zero plans for how to deal with an ASI transition that are not naive. Perhaps humanity is stuck with a choice between naive and naive squared (or maybe even naive squared and naive cubed), so I feel inclined to cut some slack to people who are trying.

If you want to bring a HEPA filter with you, the AirFanta 3Pro is the best choice. It has a very high clean speed and can be packed flat.

Big printer came down with a serious problem today, a wire to the extruder broke due to the enormous number of bends as the head moves, even with a large bend radius. Hard to troubleshoot, it caused intermittent extrusion, very similar to a previous problem when some bearings in the extruder failed. Part identified, ordered, should arrive tomorrow and hopefully be up and running soon after. The crazy thing is the digikey did not have the part. They had a 1 meter long cable, but that's not long enough. Only Amazon had the relevant part. So much for a one stop shop for electronics. Again, amazon is terribly because of *how* they do things, but they are doing things that others don't apparently know how to do, and which are important. The solution is to nationalize it or something, not just let them run rampant over all the unions, subsidize them in a million ways etc. Like canada post. Except the government would probably fuck things up and not stock the right stuff etc. However, there is no real explanation for why digikey can't do things right already... idk man, we complain so much about how bad amazon is but then other people just don't do the things that need to be done, so we all have to go back to amazon. At least they do the thing.

@NukitToBeSure I'm sure tuned in!

Figured out how to make a 3D printed fan pressure/flow tester out of $5 in plastic that's accurate to within 10% or so and I'm just enjoying blasting "We Are the Champions" before I publish it and watch it get dismissed as "self-evident" by all the people who didn't think of it because it's simple and elegant.

If successful, lithium-air batteries will kick jet fuel out of the sky and bunker fuel out of the ocean. "Mainstream lithium-ion batteries have an energy density of ~250-270 Wh/kg, while future solid-state alternatives are expected to achieve ~500 Wh/kg. Lithium-air configurations present a theoretical energy density limit of 12,000 Wh/kg, a ceiling that matches the energy capacity of conventional gasoline." CATL eyes 12,000 Wh/kg theoretical limit lithium-air EV battery to end range anxiety interestingengineering.com/energy/catl-12… Air Energy Closes Seed Round to Scale DOE-Validated Solid-State Lithium-Air Battery natlawreview.com/press-releases…

There is no need, I have never had any problem with the printed blades. They only turn at 400 rpm, which is not very fast. If I split the blade into 24 pieces and try to print them on the smaller printer and then assemble them, then I get a balance problem. However the ones I produce as a single part on the large printer are all good. I've made more than a hundred.

@open_erv PETG fan blades are a serious test of repeatability because a small weight difference becomes vibration fast. Are you balancing each blade after printing, or printing the full rotor as one part?

#4 Weekly twitter update: -The 15 motors arrived ok -Power supplies arrived ok, looks good. -Solved some problems making the printed primary blade, found a reliable filament. I had to drop the cosmetics requirements. I was trying to use matte filament because it looks nicer, but it has a smaller process window i.e. deposition temperature, feed rate, etc for a given geometry. It’s really too small, and it took me a while to realize this. Variations between batches of filament, ambient temperature and even different regions of the same part (radiant heat from the bed, stuff like that) can push it outside the process window, for both brands I tried. It’s also not as strong. -Problem with noise from the neighbors, it seems like it might go the way it came, but it disrupted progress as I had to leave the premises. Ultimately this kind of problem can be very costly to solve but I know this sort of crazy bs happens and I plan ahead and budget accordingly. I can’t stop it from causing delays except by having a redundant premises, which I do, 2 actually. Except the printers and tools are at #1. I can’t stop it from costing money, but I can budget and be efficient in other departments so it doesn’t scuttle the ship when it does happen. It’s ridiculously unreasonable but I am 40 years old and I know that’s how this shit show of a world works. If you want to succeed, you have to act according to how things are, not how they should be. -I’ve been learning to use BrambleCFD, which is based on OpenFOAM, but the simulations happen in the cloud, which is much more practical. I can do multiple at once and they finish in an hour rather than a day, for instance, as they would on my desktop. The main advantage of simulations is not just to test things without the cost (in time and $) of building them, it’s also so you can really see in there and see how the pressures, velocities, turbulence energies and so on are working. It’s that visualization that’s really valuable. -Did I mention I managed to up the pressure on the suction side of the fan by 9% by trimming the tips of the blades in just the right way? That might have been mentioned last week. Anyway I’m hoping the simulations will allow me to dig up even more improvements. Printing the blades of this geometry out of PETG took some figuring out but it’s pretty close to rolling now. -Good meeting with the Air Support Project and PHAN, with some hopeful indications of willingness to collaborate in some way. They are also in contact with the Intercept people to some degree. Everyone likes the idea of jumping in at the deep end with production all in China, but that can get complicated and even expensive, too, and it doesn’t seem like people really want to pay the costs of it, so there is always a bit of trouble bringing things together. We also want to save a couple months by doing that while it took 4 months to even consider the proposal. I think a few extra months to ramp up carefully and efficiently is probably advisable. I occurred to me only recently that there might be a print farmer in Shenzen I could find and collaborate with, and that could end up making a lot of sense to help reduce the cost of getting things rolling. So I've started searching for someone on Alibaba. -Also brief chat with Toni Colaneri, about noise measurement and psychoacoustics in air purifiers. -Found a fascinating but rather too short sort of web book on noise and psychoacoustics here, wish the guy would keep tell us more in this line, maybe if I search his name there is more: sfu.ca/sonic-studio-w… -Pretty close to getting boxes, just waiting for the box guys now, unfortunately. Not strictly BQF but: -I’m exploring trying to use AI, ideally DeepSeek, but the great challenge is to get actual quality reliable work out of it. It’s fine for low quality stuff, and processing text and other things *quickly*, but it has a terrible time producing quality results, no matter how long it has. I found a system called CowAgent I’ve been experimenting with. I was surprised and shocked to find there is no sandboxing by default, I had to install it in a virtual machine to prevent it from having total free reign over my whole computer. Pretty irresponsible on the part of the developers. I haven’t gotten very far in getting it to give *reliable* and quality advice on any subject yet, but here’s hoping as that would definitely be useful. I’m focussed on advice, for now, as that is definitely generally quite useful. I can write my own python programs, but it can take hours to research and strategize sometimes.

@DtaGuy @gothburz I appreciate the heads up. He should respect that there are actual stories like this, though. We could use a journalist here, rather than a humorist.

@open_erv @gothburz isn't, in fact, a farmer or the owner of a $400,000 combine. He's a humorist, and a good one. I recommend his pinned post, which is a hoot.

Ok but without blaming the guy, we have to ask quite seriously why people buy them to begin with, when we know this is how it is. Because therein lies the answer with why John Deere keeps getting away with it. There is a whole community of people that tell people not to do that, that design better machines. People still do it. They don't buy the better machines, either. They don't support the development of better machines. For whatever faults JD has, people flock to them because, I suppose, they believe their tractors are superior in some way. So they do actually do a good job at something, then. I hope it was worth it.

@DtaGuy @gothburz hm, ok, I consider him more of a liar, at this point, then. I don't really see the humor.