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Comment by graphe | Hacker News Reader

> There was nowhere in the app I could disable the warning, having cleaned the filter several times throughout the year I was sure it had at least another 12 months of life left in it. I decided to investigate the nightmare DRM RFID chip that was stuck to the bottom of my filter.

What's the point of having a warning of the life of the filter if OP ignores it? Why did it say it couldn't filter? If his house is dusty, and he cleaned it there's probably dust that isn't visible, he hacked the drm but he also looked for the "best air filter" and found this instead of a fan with some filters on it with no verification.

You don't just clean a filter and say I KNOW there is 12 months more.

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> What's the point of having a warning of the life of the filter if OP ignores it? Why did it say it couldn't filter?

So you'll buy a replacement filter to make the warning go away, a filter you can't (easily) buy from anyone besides the original manufacturer since they DRMed it? Obviously HEPA filters do expire eventually, but there's a perverse incentive here for the warning to undershoot the actual useful life of the filter.

>but there's a perverse incentive here for the warning to undershoot the actual useful life of the filter

Hypothetically, yes, there's a perverse incentive, but is that what is actually happening?

A clogged filter can stress the fan motor which can A) increase power consumption and B)reduce overall product life.

And it is for the consumer to decide which path to take. Not the product itself.

Until the consumer complains that the air purifier isn't doing its job and thrashes the company online, and changes for a model from a competitors.

Most consumers aren't really capable of this type of nuance.

This sounds like a completely made up problem, I don’t think this ever happens.

A clogged filter is obviously full of dust and grime, anyone who can use a vacuum cleaner can understand that

It's not unlikely. A while ago I had to deal with a laser printer that automatically reported the end of the drum's life after 15000 pages or so, even if there were no signs of stripes on the printed pages. The solution was to stick a 220 ohm resistor on the electric contacts between the drum and the rest of the printer. The printer would sense the resistor (which is present on genuine new drums too) as a signal to reset the page counter. Once the resistor gives a puff of smoke it can be removed, and the old drum can be used until its true end of life.

What does it take to burn a resistor? It sounds terrible to me. Guess it was hot all the time?

Depends on the wattage/power rating of the resistor

It was a through-hole 1/4W resistor. It burnt in about 5 seconds as far as I remember.

> A clogged filter can stress the fan motor which can A) increase power consumption and B)reduce overall product life.

you got it completely backwards, unless you have a very fancy and expensive ECM motor.

Increasing resistance decreases power draw, as the fan needs to do less work. You can test this by hooking up a vaccum cleaner to a killawatt and blocking the intake.

There may be concerns about cooling the motor, but it really doesn't take that much air movement to dissipate heat.

The whole device is a product and experience. He disabled the razor saying he couldn't use his razor blade. You're supposed touse it until it goes to zero and replace as instructed.

If you want a speaker you don't buy Sonos and say I turned off the drm, firmware and added a headphone jack.

If you want filtered air for cheap you buy a box fan with HEPA.

All of these sort of things are just based on hours used. It's like looking at your hot water heater warranty and replacing it when it's over (I live an an area where the PPM of the water is rather high and hot water heater warranties are basically calibrated for water like mine, so we do have to replace them on warranty expiration, most places you at least get a few years or double)

> It's like looking at your hot water heater warranty and replacing it when it's over

Why would anyone do that? Seems like a waste of a hot water heater that probably has a lot of life left.

People that do this probably throw out food the moment it hits the best before date too.

Changing a hot water prematurely is probable less expensive than having one blow the bottom out and flood whatever area it is in. I don't have a basement, so my central unit and water heater share a utility closet in the hallway sharing a wall with a bedroom. It's a pretty bad design flaw, as during the summer of 110°+ temps, it is unnecessarily heating the house. IR temp shows that shared wall from the bedroom side over 90° radiating into that bedroom. </rant>

That's not so much a design failure of the house, as it is a heater that is not sufficiently insulated.

Maybe, but it's a rental, so only some much to be done about that. So much was defined by me as buying a $30 roll of insulating whatever it is that then got stapled to the interior wall of the closet. Took the thermal temp down 15° on the bedroom side of the wall.

also they make hybrid water heaters that will cool whatever space they are in while they heat the water using a heat pump on top

My unit shows particle count, it's pretty easy to see when the filter is doing its job.

This is what I expected. Then I'd love a writeup on hacking the sensor to check PPM or change the percentages or to tell you when to replace it.

If someone does their research, and still buys a proprietary system that sells you expensive filters and has drm, AND chooses to get this device they must have a really good reason or aren't very smart.

The filters being DRMd was not on my bingo card when I bought my unit. Maybe that was naïve of me. But also proprietary is all that's available here. (To be clear I'm not the author, I just have an air purifier from the same seller)

Oh I didn't mean you, I think your device would be an appropriate or ideal hacking target with the PPM. I was referring to the OP who supposedly did their research and bought it anyway. I thought you had a different device.

It's surprising that your device has the reading and it would have been a great read if it was hacked to display the air pressure to gauge the longevity. If it's a different model and you're interested maybe you can flash esphome on it.

> Why did it say it couldn't filter?

We don't know it said that - it could have been saying 'arbitrary number of seconds of use has elapsed/. You could be right, but we don't know.

Xiaomi air purifiers do exactly that. Go by hours used.

At least in the older Version 3 that was still the case.

Apparently people still buy them, because they are cheap. It's the same with printers - the initial purchase price is low, then the consumables are expensive.

People really need to include the running costs into their calculations. The best deals aren't usually the cheapest machines.

Air purifiers do not filter dust and should never be bought for that purpose.

> You don't just clean a filter and say I KNOW there is 12 months more.

You do, I have been using two for about 6 years, and you can easily get at least 3-4× runtime out of authentic filters. I refer to external particulate matter sensors and ignore whatever the purifiers themselves are showing. You can also easily clean the filter with hot water, it removes any smells and has no effect on its purifying performance (again, using a couple of external sensors as reference).

Are you using HEPA filters? Which ones? What do yours filter if not dust and how do you clean them? I have some that are washable but none of them are HEPA.

> Air purifiers do not filter dust and should never be bought for that purpose.

What? What do you call the particles it filters, if not dust?

Of course you can do with a prefilter which filters out larger dust particles so they don't clog your finer filter. But most air purifiers come with that from what I've seen.

Because he is supposed to be in control. It's fine for the software to warn him of things. It's not fine for the software to enforce filter changing policy as if it was his boss. He can ignore and dismiss the warning if he wants, simply because he's the human and the machine is supposed to bend over backwards to conform to his will. There really is no need for any further justification.

> You don't just clean a filter and say I KNOW there is 12 months more.

Yes, you definitively do.

I am located in a defacto dust free location, but I use an air purifier to keep my pollen allergy under control when spring arives: This shitty DRM is telling me to change filters after X hours, because it ASSUMES it is clogged, even though it has no idea of the reality? No idea if the air is like in New Delhi or like in the north of Sweden?

Hell no! Thank you, but I can decide that on my own.

Did you buy the device? If your home is indeed "dust free" you wouldn't need this filter (and cleaning it won't clear the small things you probably want to filter, water also damages the filter). If you're using HEPA you can't tell their life just from the way they look.

If you could do that all and still chose to buy the device with drm, locked hours and a proprietary fan with filter there is flawed logic way before you bought the device. Even going forward a box fan and filter is cheaper and better.

Yes, I own three of those but an earlier version (2) that comes without RFID sensor. And I use the filter waaaaay longer than the device wants me to. This DRM is just milking money out of the consumer and producing waste, nothing else.

My eyes can probably not tell if the filter is over its lifespan, but my pollen allergy definetly can tell if it still works.

They makes sense. Have you considered using another filter? A box fan with a hepa filter or one that has appropriate sized holes may even work better for pollen and also be washable by default. Did you want the smarts in it if any? I'm hooking a plantower sensor to a purifier or you can use the Ikea air quality detector to smart trigger it. https://esphome.io/components/sensor/pm1006.html

> What's the point of having a warning of the life of the filter if OP ignores it?

Never buy a laser printer or photocopier. They'll tell you the toner needs replacing months before it actually does.

Fortunately toner is pretty easy to evaluate for yourself. And my Brother printer doesn't stop working when the low-toner warning kicks in. It also clearly shows that it's hardcoded to kick in at 1/3 capacity, they make no attempt to hide it. So I just buy a new one at that point, but I don't install it until the old one actually starts to visibly fail.

HEPA filter life is a little harder to evaluate using basic human senses.

great, so we can't use ink jet because of their shenanigans, and now you're saying don't buy laser or photocopier. so how to i put ink on dead trees?

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