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Air Con: $1697 for an on/off switch

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Re: Air Con: $1697 for an on/off switch

#331

Post by sandworm101 »

>> This control system is operated by a cheap POE powered Android tablet on the wall of the living room.

>> actively monitor temperature and adjust vent opening angles and fan speed to achieve desired temperatures across multiple zones.

Who actually wants this junk? Air conditioning is a simple series of bang-bang controllers. A handful of relays turn things on and off as needed. There is no need for "vent opening angles". Vents are open or closed, pumps on or off. The thermal mass of the structure keeps everything within a narrow band as systems cycle. And then the oxymoron buzzwords like "actively monitor". No. Unless it has a little arm to spin a wet bulb, it passively reads the temperatures and sends and over/under signals as needed, something that for decades was done with a blob of mercury on a spring. The moment this system even hiccupped, I would gut it and replace with basic 4-wire thermostats in each zone.

Re: Air Con: $1697 for an on/off switch

#332

Post by jerf »

audunw wrote: post #220
zeroflow wrote: post #207

Earlier quoted context omitted.

I'm offering you a different viewpoint: They made the analysis, how long the flash will live and saw, that it will make it out of the warranty period. Thus they did not opt for more durable and expensive flash and/or software change. I've seen this myself before. One process step before release of the control module was a write cycle analysis to make sure the unit will live for at least 10 years (i think) before the…

You're both missing one of the more likely explanation.. that nobody gave much thought about how long the device would last. "It's solid state electronics, it'll probably outlast the warranty anyway".. I can imagine an aircon company puts a lot of effort into analyzing the air-conditioning unit itself to make sure it lasts at least as long as the warranty, with good margin. But I can totally see them winging it on an…

I generally treat my tablets and phones very well. I wouldn't trust a tablet, at scale, to last much beyond three years. By "at scale" that means, say, a replacement rate of less than 10%.

By contrast ACs are on the decadal scale.

Integrating a tablet can't work. It's a dumb idea from the outset.

Similar hardware can work. There are touchscreen UIs that do last for a long time, especially on an AC unit where they're not getting used all the time. But they aren't tablets. In particular I'd finger the lithium ion batteries optimized for tablet-style usage as something you don't put into a system you want to last about ten years. Most of my tablets "die" when the battery just becomes unusable.

And you probably want an LCD chosen for robustness rather than being the cheapest possible high resolution display... again, plenty of LCDs can last for a long time, but the trifecta of "high resolution", "cheap", and "lasts a long time" is asking an awful lot for a fleet of systems. ("Cheap" and "lasts a long time" is, by contrast, readily available; it just won't be pretty. But it'll work fine.) And by "high resolution" I don't mean "retina display", just anything suitable for a tablet. Ye Olde 640x480 is plenty for an AC display, even in monochrome.

You want something pretty, give it a way for a real app to access it on the network. Except don't bother, really, because there's no way you're going to maintain that for 10 years either.

Re: Air Con: $1697 for an on/off switch

#333

Post by lolinder »

prmoustache wrote: post #316
gwd wrote: post #285

Earlier quoted context omitted.

Consider the following scenario: 1. Someone owns one of these systems which is functioning perfectly well. 2. They stumble across a link allowing them to download the controller app, and so they install it on their normal tablet, expecting to be able to control the system from their tablet 3a. It doesn't work, so they contact technical support. Technical support wastes a bunch of time before figuring out why the app…

But you could have a warning at the start of the app without rendering it unusable that would pretty much solve old points.

You've clearly never worked in tech support. People who are likely to go through the steps that OP described aren't going to read the warning.

Re: Air Con: $1697 for an on/off switch

#334

Post by sidewndr46 »

gambiting wrote: post #317
nyanpasu64 wrote: post #19

> The original ezone tablet had been running Android 6.0, this Samsung was still on 5.0 but I didnt think that would cause any issues so I got started on doing what was clearly missing: The required apps. All ezone apps are available both on the Advantage Air website and the apkpure site. I only learned of the apkpure site from a post claiming he had been directed to it by a AA tech support person. Redirecting your c…

I was just reading an official Volvo technical bulletin for an issue that can occur in a latest XC90....the manual literally says "download this patch, load it into the patching software, you will get a warning about the patch not being signed and invalid for this car, click ignore and then click proceed anyway". Why even build those warnings in, if you're going to make your own mechanics ignore them.

Isn't this exactly what SolarWinds did when someone bypassed their build system and inserted a backdoor? Made a tweet about how users could just accept the unsigned build?

Re: Air Con: $1697 for an on/off switch

#335

Post by abanana »

lolinder wrote: post #330
yurishimo wrote: post #302

Earlier quoted context omitted.

Maybe they moved? In my experience, IKEA furniture that isn't solid wood (more and more of it is heading that direction to their credit) tends to not make it more than 1 move. I just got done (mostly) reassembling a wardrobe. It's a bit more wobbly around the edges. I'm not sure if it's because I didn't put the shelves back in the exact spots (wasn't thinking and didn't label them during disassembly) or if it's somet…

I tend to assume that IKEA furniture shouldn't be actually taken apart once put together, and so far that's worked out fine for us. There are some pieces that are obviously repeatable (table legs screwed into metal mounting brackets) but with a lot of the steps you can feel as you're doing it the first time that it's not going to work well if you have to undo it.

True. Adding a few 2" screws (into pilot holes) makes an enormous difference to the rigidity of their (e.g.) wardrobes and kitchen units. Even on first assembly, but especially if you have to take apart and rebuild.

Re: Air Con: $1697 for an on/off switch

#336

Post by erinnh »

pzlarsson wrote: post #120
datahack wrote: post #100

Earlier quoted context omitted.

You think this is bad? Try swimming pool equipment.

I think home EV charging equipment is heading in the same direction as well. Very few have local and open APIs and instead depend on the vendors cloud service for control.

There is OCPP (Open Charge Point Protocol). There's quite a bit of choice in supported wallboxes. Here is Europe at least.

Re: Air Con: $1697 for an on/off switch

#337

Post by zrobotics »

teslabox wrote: post #48
SOLAR_FIELDS wrote: post #28

Earlier quoted context omitted.

I highly recommend people who live in hot environments to keep a spare capacitor on hand. Even if you know how to fix it, if the AC dies when your local HVAC supply store is closed (eg not between 7am-7pm Monday through Saturday usually) you’re either stuck paying out the nose to a contractor who has one on hand during emergency hours or you’re sweating it out waiting for the store to open. While they are readily ava…

> But HVAC supply shops will sell them to you, you don’t need to be licensed or anything to buy them. My local HVAC supplier doesn't sell to non-licensed people. I think they don't like dealing with returns from people who don't know what they're doing. I needed a 24vac transformer once. My dad used the same HVAC company for his office for a long time, they still remembered him, and had the part I needed in stock. My…

A lot of supply houses only sell to people with an account setup. It's not that you need to be a liscenced contractor, they just aren't setup for retail sale. This often extends to not even having a till, customers create an account with net 30/60 terms.

A good way to check if a place does retail sale is to ask for the city desk when calling in.

Re: Air Con: $1697 for an on/off switch

#338

Post by datavirtue »

gstar wrote: post #88
thrtythreeforty wrote: post #82

Earlier quoted context omitted.

What the hell, why does a control system need an AES-secured control channel at all? The only possible intention is to make interop more difficult. If they wanted security then they wouldn't use a hard coded AES key.

It 100% is designed so that you have to use their hardware.

Companies don't encrypt anything unless required. Except for code and databases...they encrypt and obfuscate those to keep people running back to them.

Source: my customers

Re: Air Con: $1697 for an on/off switch

#339

Post by jandrese »

MaxikCZ wrote: post #162
amiga-workbench wrote: post #143

Earlier quoted context omitted.

Surely it can't cost much more to go for a larger eMMC chip and have it massively over-provisioned with plenty of space for wear levelling? The underlying flash memory is trash and the controller already does a ton of heavy lifting to keep the data coherent.

But then you are not only making your build price higher, you also have less revenue as year pass. And its hard to market.

It's a $1,700 bottom barrel android tablet, there is plenty of profit margin available.

Re: Air Con: $1697 for an on/off switch

#340

Post by gstar »

FLT8 wrote: post #322
gstar wrote: post #307

Earlier quoted context omitted.

I have something slightly different 1 is RS422 B 2 is RS422 A 3 & 5 - GND 4 & 6 - VCC Not sure what 7 and 8 do.

Interesting, not sure what's going on there then.. how recently was your system installed? Maybe they have updated the pinout on newer models? I'll go back and check though.

You're right! The serial bus isn't encrypted!

I got inspired, and have plugged in my scope, and then an RS422 to serial adapter, and I'm getting XML encoded (weird) CAN messages, which I presume are the same as what's on the CAN bus exposed on some of the control box's ports. I'll get out the can analyser tomorrow and check.

Now the trick will be to reverse engineer this protocol. Here's a tiny sample:

  setCAN 0201000000236000000000000 getCAN 1 Ping ackCAN 1Ping setCAN getCAN 1 Ping ackCAN 1Ping setCAN getCAN 1 Ping ackCAN 1Ping setCAN getCAN 1 Ping ackCAN 1Ping setCAN getCAN 1 Ping ackCAN 1Ping
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