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/
Dehumidifiers already do that. They’re equipped with hygrometers that kick the machine on or off depending on the relative humidity. It’s old tech and it’s pretty reliable, wifi isn’t really necessary for it.
The built-in hygrometer’s not necessarily going to be as good as a well-designed home automation system, especially if the fan’s not running all the time, so it has to wait for damp air to diffuse into the machine. It also lets you do other things, like not bother turning the dehumidifier on if there are open windows if you’ve got some way to detect that, or report the humidity to something that will graph it. It’s not stuff that most consumers will care about, but a microcontroller with WiFi like the ESP8266 or ESP32-C3 costs less than an accurate hygrometer chip, so it doesn’t make much, if any, difference to the final price, particularly if the product was going to use a microcontroller anyway.
It’s ironic that you can implement all this cool automation for a device but in the end still have to manually lug water to it.
Well it’s a **de-**humidifier. You need to lug water from it. For the dehumidifier in my basement, we have it hooked up to a hose that takes the water right down the drain.
But I do take your point, it is pretty funny.
Like how every source of power is still steam since before the industrial revolution.
Just most sources of power. Photovoltaic, wind and hydro aren’t steam based.
Almost no cars, trucks, or tractors are steam based anymore. I believe most ships are ICE as well, not to mention rockets, and animal/muscle power. As such I’d need a very deep analysis of the situation to believe any claim. (deep because in an ICE a large part of the power comes from burning fuel producing steam, so we can start debating how much of an ICE is steam - have fun).
In any case my local electric utility generated more power from wind than all customers used last year, so I can make a good claim most of my power isn’t from steam. If your utility isn’t in the same situations or close you should be demanding they get with the times.
And your moms power is hip based.
I’m not going to knock her putting them to good use! It’s done well by her so far. 👍
That’s the spirit!
Ok, two things.
First, the cost of the Wi-Fi chip is clearly not the issue here. The real expense/concern is the effort and software mechanisms needed to secure that network connection. Connecting to the Internet is easy, securing that connected device is hard.
Secondly, at some point you still need the hygrometer, there’s no way around that. Either your dehumidifier is tracking humidity, or your home automation system needs to track humidity. And you can’t like… get that data from the web somehow, you need a local sensor, and it will generally only make sense to have it in the same room as the dehumidifier (meaning not necessarily where other smart home components are set up).
You’re missing my point. It’s likely that the cheapest way to design and build a dehumidifier these days will already include a microcontroller interpreting results from a digital hygrometer because these components are cheap and easier to work with than purely electronic/electromechanical designs with no microcontroller. The cost of switching from a non-WiFi/Bluetooth/Zigbee microcontroller to one with one or more of these networks is negligible, and once you’ve got it, it’s not meaningfully more expensive to pay a software engineer to expose the on/off switch and hygrometer readings via that network and have the marketing people write Smart! Now with WiFi! than it is to skip it and pay the marketing people to come up with some other nonsense to put on the box. If you care about security as little as the average IoT vendor does, then it’s nearly free to turn a dumb device into a smart one, so if it makes a handful of extra people buy the device, manufacturers will make things smart. For a dehumidifier, there are reasons why a handful of people will prefer a smart one, so smart dehumidifiers get made.
Well this part is definitely not true. A microcontroller and Wi-Fi chip are definitely more expensive than a wire, a variable resistor and a knob, which is all a purely electro-mechanical system would need in addition to the hydrometer.
The fancy digital version wouldn’t be a lot more expensive, but it certainly wouldn’t be the cheapest way to go.
That said, I think you’re right that most companies will opt to go the fancy digital route to try to sell a “smart” product with more features. But then I expect there will also always be companies that manufacture simpler, cheaper products as well.
The cheapest hygrometers these days only have a digital output, and a wire and a potentiometer aren’t going to be able to query an i2c bus to ask the hygrometer what it’s measured without the help of a microcontroller (and the microcontroller might be cheaper than the potentiometer anyway depending on the specific model of each - have you actually looked at the 2025 prices of things before making assertions about what they cost?). The analogue component of a hygrometer that actually does the measurement gives fairly small changes to the resistance/capacitance (depending on the kind of hygrometer), so the results need amplifying. If you’re measuring on the same chip, you can get away with a simpler amplifier and digitally compensate for any nonlinearity, whereas to get a strong enough signal to make it to the rest of an analogue circuit without much degradation, you’d need an amplifier that ends up being more complicated than doing everything digitally.
Look, I’ll be honest with you, I’ve never built a dehumidifier (I’m sure you’re shocked). I don’t know what exact components tend to be used. What I do know is that I have a fairly new dehumidifier and we have another one from probably the early 80s. Somehow they both work. Again, I’m not sure what components were used in the older model, but given the age I’d be very surprised if the electronics it uses would be more expensive to manufacture than the newer one.
Really, I think the idea I’m trying to get across is just that you can always aim lower. Sometimes the goal isn’t achieving perfect precision, but rather achieving something good enough. Take toasters for example, most toasters don’t have a timer at all. They have a little piece of metal almost touching a contact. When you turn the toaster on, that metal heats up and it bends until it touches that contact, ding toast is done. And when you turn the little dial from light to dark it just moves that piece of metal slightly further from the contact. My point is, it’s not exact, it won’t be the same on every toaster, and it will probably shift over time. It’s a low tech solution for something that could absolutely be done in a more modern, more precise, and still inexpensive way (a simple timer). But it’s cheaper and simpler to just do it the old way, and for many applications, that’s fine.
Hell, I’m certain there are dehumidifiers on the market that don’t have any kind of humidity sensor at all. Even simpler…
If you don’t have a sensor then that is cheaper in the short term, but it quickly wastes a lot of energy running when the humidity is under control. For a dehumidifier you need more energy to get lower so the room well generally will be fairly consistent not too low humidity even as outside humidity changes, but you will use a lot more energy than a system that turns off when humidity is good.
there are purely mechanical systems that used to be used. However they have some weird machining requirements so it isn’t clear they are cheaper than a digital system (this partially depends on volume - make more and the machining gets cheaper per unit). The digital system is as we already have established is very cheap and lets you put buttons and LEDs on the unit for a few cents more - this is far more valuable to marketing than the possible savings (if any!) from a mechanical control.
That’s fundamentally where you’re going wrong, then. 1980s electronics (for a dehumidifier, it wouldn’t even be electronics, it’d be electromechanical) are often much more expensive than modern approaches, and even when they’re cheaper, it’s typically not by much. Over time, it’s got cheaper and cheaper to precisely make small things, but the costs of materials haven’t meaningfully gone down, so the 1980s approach costs about the same as it did back then, whereas digital electronics have plummeted in cost. Now, anything where the best approach was electromechanical rather than electronic is almost certainly cheaper to do digitally.
Another great example of being out of date. Fifteen years ago, cheap toasters almost always used a bimetallic strip and the dial controlled the position of the contact it touched so it would have to bend more or less before it disconnected. In nearly every modern toaster, however, you’ll either have something like a 555 timer and the dial will control a variable capacitor that changes the frequency of an oscillator to make it count slower or faster, or it’ll have a dedicated toaster control chip like the BCT5512 and the dial will control a potentiometer that a capacitor drains through. Mouser list the PT8A2511PE toaster controller for £0.111 in bulk, but the cheapest bimetallic switch they carry (which is too basic for a toaster because it’s got a fixed switching temperature) is the F13A17005L360100, which is £1.93 in bulk, more than seventeen times the price. (I suspect they used to have cheaper ones back when toasters still used them, and they’ve been discontinued now toaster manufacturers have stopped ordering them.)
A lot of the time, the old way is more complicated and more expensive. Technology doesn’t just let us do things we couldn’t before, it also lets us do existing things in new, better ways, and being cheap is one of the most in-demand things. It’s lower tech to hire ten labourers with shovels for a week to dig a hole, but it’s much cheaper and faster to hire one labourer with a digger to dig it in an hour.
Having no sensor at all is certainly the cheapest way to do it, but we were talking about ones that do have a sensor, and whether, once you’ve opted to have a sensor, there’s any major cost to making the device smart. If you’re aiming so low-end that you don’t even have a sensor, then you’re clearly not concerned about the marketing benefit of extra features, so wouldn’t bother making it smart.
So, first off, smart devices shouldn’t need to connect to the internet, only the local network. I have everything connected to Home Assistant, and then for access outside the house I have HA connected to the internet, meaning I only have one point I need to secure.
On your second point, I think the poster above was talking about having both an in-built as well as wifi-accessible external sensor. It makes it possible to have a more powerful dehumidifier in one space, running to a lower humidity than needed based off what’s going on in other rooms. Then have that air circulated by other fans, etc.
No it doesn’t. Those micros go for $1-2 bulk, but capacitive hygrometers are 10x cheaper.
I can get a board from AliExpress with an ESP32-C3 on it with free shipping for £1.10, so I’m not inclined to believe the £0.765 unit cost for a 5000-part reel from Mouser is really the cheapest way to get them in bulk as the other parts on the same board and the shipping have to cost something.
The cheapest hygrometer that Mouser sell is £0.748 per unit for a 10,000-part reel, and its datasheet says not to leave it for more than 60 hours in greater than 80% relative humidity (which is a pretty likely scenario for a dehumidifier) as it’ll drift, and if it happens often, it’ll age faster. You need to spend more to get rid of that restriction. I’ll concede that the accuracy penalty if you cheap out isn’t as bad as I thought - I’d not actually looked at a datasheet to see how badly modern hygrometers would drift, I just knew that they did - so plenty of manufacturers wouldn’t care, but the parts are still comparable prices, not a factor of ten like you’re claiming.
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?