[gstar]

OMFG; I am in Perth, I have the same system, the very same problem and solved it almost the same way and was in the process of writing it up.

The system uses RS422, with a base64 encoded AES key in the aaservice binary, and I was contemplating building an esp32 based open source implementation of the controller.

That's a crazy weird coincidence.

[gstar]

Incidentally, if you root your tablet you can just change the build.MODEL to "MyAir5" and everything will work on a third party tablet.

[gstar]

Oh, and you just need one of these and a TTL to RS422 converter off aliexpress to replicate the interface:

https://www.aliexpress.com/item/1005005918675239.html

The connectors on the small RJ45 daughter board are JST-SH 1.0

The yellow lead puts out 4.2v to replicate a Li-Ion battery (as far as I can tell). You can ignore this.

Red is positive

Black is negative

Green is usb d+

Blue is usb d-

[rpearce9]

In case it's helpful to anyone, I put this together to drive our Advantage Air system:

https://git.nethack.net/rob/aircon

Essentially it just talks to the android tablet API to do things so it's no help if (when) the tablet dies, but it means I can do things like:

- have the entire unit turn on/off as needed based on average zone temperatures

- open/close vents based on room owners' devices being online, or temperatures of nearby zones

- dump zone temperatures to influxdb

[lelandfe]

Nice use of Telegram as a cheap logging tool

[thrtythreeforty]

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.

[gstar]

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

[marcus0x62]

Anti circumvention laws don’t require good locks to provide the manufacturers a legal cudgel to use against anyone with the temerity to think they have the right to use and fix things they have paid for. The law (DMCA in the US, it looks like something called the Digital Agenda Act in Australia) is the real lock, not that AES key.

[c_o_n_v_e_x]

In theory, connected devices that control large energy loads ("large" on a household level of energy consumption) can be coordinated at scale to "attack" the power grid via instantaneously switching 1000's of units on and off at the same time.

That being said it's more likely the hardware mfg is just trying to claw in more margin.

[FLT8]

I've got one of these systems too. Mine hasn't died yet, touch wood, but I was concerned enough about the possibility that I went as far as documenting the comms protocol and starting to design a pi hat to talk to the main control board.

I should really write that up at some point too.

[jamesholden]

Do it! I don't live in Australia or have on of these systems, but I was intrigued by how the OP had gone around the company to save themselves 1500! I'm curious to see how people are resolving things like this, so that if I have issues myself sometime, I have ideas on where to start or what is necessary :)

[virtue3]

sounds like the memory storage is failing on some sort of logging systems for these to be going down at the same time-ish (same number of logs per day written etc over cheap flash).

Shame on this manufacturer.

[sumtechguy]

It is a conversation I have had with many a jr dev. 'ok you are logging this how much space is that going to take? how long do you want to keep it? what is your rotation schedule?'

I usually get the 'oh did not think of that' because logging is a serious afterthought in many cases. It is boring and you just drop in log4j and log away right?

[radicalbyte]

Reading the original post, wouldn't be a super cool idea to make a little ESP or RPI based system which acted as a controller for the airco and a network bridge? Then literally anything could interface with it. You wouldn't even need to wire it up. No need to install some shitty app from a company who are quite clearly c*ts.

[squarefoot]

I'm sure that they made things more difficult by employing proprietary hardware wherever they can (also to discourage competition), but yes, there are a bunch of sensors and actuators in there and any board with the appropriate i/o capabilities should be able to interface to them, however writing a working firmware would be next to a nightmare: how do you find developers who want to spend months reverse engineering an AC and also know enough about ACs to put together something that works? Replacing household appliances brains with open counterparts would be a heck of a business opportunity to revive or prolong the life of dead/obsolete products, however I guess finding people who are interested enough to do that with FOSS, essentially selling only hardware and installation services would be really hard.

[stavros]

What evidence do you have that the company is composed of cats?

[dbetteridge]

For a small place there's a lot of sandgropers on HN somehow

[marcus_holmes]

Timezone effect, I think. Just us and the whole of East Asia online now. The Poms and Europeans are just about to wake up, and the Americans have logged off for the night.

[TechDebtDevin]

For those also wondering:

https://www.quora.com/Why-are-West-Australians-called-sandgr...

[gstar]

Speaking of sandgropers, I do understand Advantage Air are based in WA - so it's fairly likely they're reading this!

[mst]

I'm sure the timezone will tick over to the sheepshaggers instead shortly.

[ranebo]

Oh wow, that is crazy! That sounds awesome so please still write it up and I will link. myreal.name@gmail

[ivraatiems]

Almost like all the tablets fail around the same time because they're made in the same shoddy way, forcing system replacements every so many years...

[Cthulhu_]

They skimped on the tablet, grabbing a <$100 device for cheap. It should be a ruggedized / semi-industrial device with an expected lifetime as long as the device it controls, so at least 15-20 years.

[f1shy]

Related: https://www.youtube.com/watch?v=WCpVGwSJoyQ

[fatcow]

another perthian! w00t