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gstar

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gstar
·2 года назад·discuss
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:

  <U>setCAN 0201000000236000000000000 </U=ce><U>getCAN 1 </U=00><U>Ping</U=db> <U>ackCAN 1</U=aa><U>Ping</U=db> <U>setCAN </U=b2><U>getCAN 1 </U=00><U>Ping</U=db> <U>ackCAN 1</U=aa><U>Ping</U=db> <U>setCAN </U=b2><U>getCAN 1 </U=00><U>Ping</U=db> <U>ackCAN 1</U=aa><U>Ping</U=db> <U>setCAN </U=b2><U>getCAN 1 </U=00><U>Ping</U=db> <U>ackCAN 1</U=aa><U>Ping</U=db> <U>setCAN </U=b2><U>getCAN 1 </U=00><U>Ping</U=db> <U>ackCAN 1</U=aa><U>Ping</U=db>
gstar
·2 года назад·discuss
Not always - if it's used as a bus, it's 2 wire.
gstar
·2 года назад·discuss
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.
gstar
·2 года назад·discuss
Interesting! Yours is a different rev to mine, and a different chip. Can you post photos of both sides please?
gstar
·2 года назад·discuss
No, sorry - I may be able to buzz one out of the a/c controller later on.

I do, have 2 spare USB-C to JST-SH adapters that suit the round advantage air circuit board if anyone wants one (Perth, Free). Email in profile.
gstar
·2 года назад·discuss
It's an FT312D, which is a purpose-built android thingy that presents a serial port and allows the tablet to charge.
gstar
·2 года назад·discuss
Speaking of sandgropers, I do understand Advantage Air are based in WA - so it's fairly likely they're reading this!
gstar
·2 года назад·discuss
It 100% is designed so that you have to use their hardware.
gstar
·2 года назад·discuss
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-
gstar
·2 года назад·discuss
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
·2 года назад·discuss
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.