- cross-posted to:
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- cross-posted to:
- [email protected]
Title text:
It’s important for devices to have internet connectivity so the manufacturer can patch remote exploits.
Transcript:
[A store salesman, Hairy, is showing Cueball a dehumidifier, with a “SALE” label on it. Several other unidentified devices, possibly other dehumidifier models, are shown in the store as well.]
Salesman: This dehumidifier model features built-in WiFi for remote updates.
Cueball: Great! That will be really useful if they discover a new kind of water.
Source: https://xkcd.com/3109/
And how does a well designed automation system measure how much moisture in the air? There must be some kind of measuring device that measures moisture, a moisture scope! Ooh wait let’s latinize it to make it sound more impressive and sophisticated a hygro…me…ter… oh… uh… this is embarrassing.
In the UK, it’s common for electric showers to be on a separate isolator that needs to be turned on before they’ll heat up, and it also activates an extractor fan, and most people turn it off again when they’re done showering. It’s pretty simple for a home automation hobbyist to swap the regular isolator switch for a smart one, and then their system can know when they’re about to shower and activate the dehumidifier immediately. This can be much better than waiting ten minutes for enough humidity to diffuse into the dehumidifier for the humidistat to activate then waiting another ten minutes for the cold side to cool enough for any dehumidification to start.
I didn’t say a home automation system would be measuring the humidity and reacting. The opportunity to do better comes from the potential to be more proactive if you can figure out a way to tell a computer about impending humidity.
But dehumidification doesn’t need to be proactive, it’s entire point is to kick on when there’s too much humidity and turn off once it gets to where it’s set to. This is the kind of building a solution to a problem that doesn’t actually exist.
And you’re vastly underestimating how quickly diffusion works, especiallu for water vapor in air. When I take my shower in the morning the air very quickly saturates with humidity. I don’t have a very dry half of the room and a very humid half of the room. The entire room is humid. It doesn’t take 10 minutes for the humidity to diffuse into the dehumidifier. And then I leave the bathroom door open after which the humidity very quickly dissipates and equalizes the relatively high humidity of the very small bathroom into the comfortable humidity of the very large everywhere else that the small amount of humidity will have a negligible impact on.
I’m failing to see how putting more unnecessary stuff between the hygrometer and the cooling loop of a dehumidifier makes it better.
I was going to share a graph from when I put a DHT20 hygrometer in my bathroom to prove to my family that the humidity was the cause of the mould and they should stop turning the dehumidifier off when its built-in hygrometer said it should be running, but unfortunately, it was long enough ago that Home Assistant decided I no longer need my one-every-ten-seconds readings and now only shows hourly readings, which aren’t enough to prove my point here. You’ll just have to take my word for it that when I did this test, I was surprised to find that although the humidity at the other end of the room started rising quickly after the shower was turned on, it peaked fifteen or twenty minutes after it was turned off again because diffusion without something like a fan or a draught moving the air around can be really slow.
My bathroom’s a weird shape as it’s long and thin and has a weirdly high ceiling at one end, so it’s not going to have typical airflow, but it is a real bathroom that really exists, and I did have data in the past showing it dried out faster if I manually turned the dehumidifier to maximum (so it would run even if its hygrometer said not to) ten minutes before turning the shower on than if I did it immediately before turning the shower on. Whether I’m going to shower in ten minutes is something I can know but a hygrometer can’t. This isn’t even really related to whether the dehumifier is smart as mine isn’t and I can operate its switch as easily as I could operate a smart switch, and my shower isn’t electric, so there isn’t a switch I need to operate before using it that could be made to do two jobs
It sounds to me like your problem is human error, not the lack of a smarter machine. You can’t engineer your way around people being morons. The greatest engineering minds have figured that out years ago.
So you think the reason a hygrometer can’t detect humidity ten minutes before it exists in order to start cooling the dehumidifier’s compressor to the temperature it needs to be to start working is human error?
No I’m saying you told your family to stop turning off the dehumidifier and they haven’t stopped doing that. No amount of home automation or smart devices is going to change your family turning the dehumidifier off. You don’t have a dumb system problem, you have a dumb people problem. And unfortunately a dumb people problem doesn’t get solved by a smarter system.
Dehumidifiers are already automatic. Black mold isn’t going to take over your bathroom in 10 minutes.
Turning the dehumidifier on ten minutes early means there aren’t ten to twenty minutes where the shower’s running with no dehumidification where condensation is able to settle on all the walls unimpeded, and the extra condensation takes a couple of extra hours to dry out again. Regardless of whether my family try to turn off the dehumidifier prematurely (and I only mentioned that as why I’d originally set a hygrometer up to graph the humidity in the bathroom, not as an ongoing problem), if that happens several times a day when someone showers, that’s more than enough dampness for black mold to form.