Open_ERV

I am building 1000 of the world's quietest fans, for use in air purifiers. There is a crowdfunding campaign, see for details/signup.

[Open_ERV @open_erv]

There are some interesting technologies like reaction injection molding and vacuum casting or even just resin casting without vacuum which can help here. Secondly, clever techniques and good materials etc can increase printing speed and quality enough it can compete favorably with some approaches in low volumes. The drone guys in Ukraine have proven this.

[Enezator @Enezator]

Recorded in March 2025 and meant to be released only after her passing, this is Jane Goodall's final message to the world 🥹❤️

[Open_ERV @open_erv]

There has been tremendous progress on outdoor air pollution, after much foolish destruction for a long time. London, Beijing and a few other cities have had some success at tackling the issues at the sources. The thing is it takes a ton of doing to pollute the great outdoors. Thus there is a ton of people available to solve the problem. Even wildfires there is a lot we can do to prevent them. I am big on air purifiers partly because they are the ounce of prevention that pays in spades, but for most pollutants we can go up the causative chain even further and that works even better and I try to emphasize this.

I would never want to become someone selling the idea that we should hide in boxes with machines while the outside burns.

[Open_ERV @open_erv]

@ThisHouseFresh Unfortunately the ai detectors are also generally based on a type of AI. They have considerable false positive and negative rates.

[Open_ERV @open_erv]

@Engineer_Wong @ghhughes Oh ok sorry, they usually look different

[Open_ERV @open_erv]

@macjshiggins I do, and that they suddenly shut down due to some random crapitalist bullshit, leaving a ton of people seriously screwed. I think in some cases the people got a little organized and managed to take over? Like the kellog factory in venuzuela.

[Open_ERV @open_erv]

One of the postal services *still* broke the Big Quiet Fan I sent for testing. The one I packed well enough for a tank to run over it, or at least enough I could stand on it no problem. A solid wood crate, it used up my entire supply of packing foam too. They still broke it! Apparently they dropped the whole package from considerable height or something, it looks like the inertia of the drop led to the breakage.

You could say that I need to make it stronger, which I can and will do in the future, but also that's not really a fair criticism. It was plenty strong enough for all practical purposes. You don't drop a heavy package. The easiest, most reasonable way to solve/avoid this kind of thing is just to be careful.

[Yanis Varoufakis @yanisvaroufakis]

Now that Gaza lies in ruins—shattered, like a beloved face after a long brutality—Israel moves with a terrible confidence to the next act: The act of leaving every soul there not merely wounded, but permanently disabled. Injured, sick, hungry, homeless, without work, without hope. This is not war’s collateral damage. This is design.

As my friend Gideon Levy writes—and he knows, he knows—this is the prelude to expulsion. Think of it: a society without teachers, without doctors, without social workers, without engineers, without clerks. That is not a society. That is a holding pen. A slow erasure. And when nothing functions—no school, no hospital, no office, no heart—then it becomes ‘easy,’ they tell themselves, to scatter the people to the four corners of the earth. Like seeds from a broken pod, except no soil will take them.

We must name this. Not with rage alone, though rage is honest. But with the cold, clear tears of recognition: they are making life impossible so that departure becomes the only ‘choice.’ And the world watches, adjusts its spectacles, and calls for restraint. Restraint! There is no restraint in a slow drowning.

[Open_ERV @open_erv]

@babadookspinoza It's the evil people that ruin lives, not the arrest itsself. There has to be less evil, and that will require some resistance/protesting, however I do agree a wiser strategy needs to be used, given how much they can nail you through such mechanisms.

[Open_ERV @open_erv]

@ThisHouseFresh @SmartAirFilters @SmartairUk oh, it also seems to be quite a bit more than a tempest though? It is perhaps only a start. However I do think in general the challenge is to advance by doing better than the next best thing already on the market.

[Open_ERV @open_erv]

@ThisHouseFresh @SmartAirFilters @SmartairUk Oh nice, they are leveraging some of the lessons learned in the grassroots. Us that a furnace filter though?

[Open_ERV @open_erv]

Interesting guy doing small scale production and engineering in the US. I am not a big fan of the domestic production thing, I think the guys in China are very good at what they do and we should work together. However, fundamental power to design and produce what is needed has a sort of negative externality that is not easily captured by the purchase price, and it's probably a good idea for us all to keep at least a little such power, just like keeping some extra food in the pantry for emergency. No farmer or restaurant operator would likely object to that.

[Parth Ingle @parthingle_x]

https://t.co/Hb1FQPTIPz

[Open_ERV @open_erv]

@squirrelthere @parthingle_x Business to business websites like alibaba. It takes a long time to get a good deal, find good business partners, if you want good stuff reliably at a good price.

[Open_ERV @open_erv]

It really depends how well the off the shelf machine fits your needs. A specific machine that does exactly what you need can be worth designing it. Then you will be tempted to sell the machine to others, then you realize how much more work it is to make something that others will be happy with, not just good for internal use. Then you realize how much work you saved compared with the company that designed that off the shelf machine.

I do not know much about winding machines but I would have advised to not build your own milling machine, I know a lot about those.

[Open_ERV @open_erv]

Sounds like you are rediscovering what we were doing/why, at OSE. To be fair those off the shelf machines work pretty well for a lot of people, and if you were to sell the machines that you made you would probably charge a similar amount for them. The labor counts.

I would not build your own machining tools, machine tools are very general purpose and good ones area available at relatively low cost. You are probably not going to get the speed increases you seek from increasing the spindle power. There are limits on the strength of the tools and so on that will pull you away from that theoretical ideal.

The bottom line is that bringing production into the country has benefits that are long term and serious but are not reflected well in purchase price. It's like a negative externality.

I do agree there is great potential in what you are doing but you gotta stay on your toes, there are no easy answers here, and the best case scenario on a personal level is you get an honest job and be your own boss. There is no get rich scenario here, I think. And I say that doing something kind of similar, I am planning to make my Big Quiet Fan in Canada, including much additive manufactured parts. I do need one and only one mold and it has complicated things enormously.

[Nathan Kalman-Lamb @nkalamb]

Canada is about to go Full McCarthy against anyone critical of Israel for its horrifically genocidal conduct.

[Open_ERV @open_erv]

@Engineer_Wong @ghhughes Why not use ndir then?

[Open_ERV @open_erv]

@brownecfm Why have we not talked?

[Open_ERV @open_erv]

I spent most of Sunday cobbling together a big quiet fan from old prototype parts. This one has extra power. It was installed at Foulab, where there is a lot of background noise (usually other fans in the computers). Thus the extra noise from giving it some extra power is harmless.

To allow it to put out extra power, I put the driver board upside down at the exit, the extra cooling allows extra power. It has 4 redundant safety measures, one at the power supply for overcurrent, the driver chips themselves, stall detection in the motor driver microcontroller, and a final thermal fuse on the motor itsself. You don't really need any of them but better to be safe, only two of them I deliberately arranged for, the others are just along for the ride. Because it is cobbled together parts, and therefore not thoroughly tested, this is advisable.

I noticed when I dismantled the old fan that there was actually dust on the inside of the system. I have added it to my list of things to do to check the output and input of they system to ensure that it is still removing particles the way we think it is, because the filters are pretty dirty. The study by the CR box foundation found that the main source of CADR loss is reduced efficiency as the filters become dirty.

The air at Foulab really really needs the air purifier, it is very dusty and dirty. A lot of dust comes through the cracks in the ceiling (floorboards from the floor above are exposed) and elsewhere in the building. We also often have fairly large gatherings and in winter there is no deliberate means of obtaining fresh air.

I would like to cobble together some TW4 parts to make an ERV of large capacity that could go in the window, but it would be a little expensive/time consuming.