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First analysis

A project log for Hitachi air conditionner controller hack - ESP01

The purpose of this project is to manage my hitachi air conditionners with the Home Assistant using low cost ESP-01.

VinceVince 05/18/2021 at 17:390 Comments

First thing first

Here the first analysis of the serial communication between the SPX-WFG01 and the A/C catch with 2 serial adaptators connected to my laptop.

The communication consist of ;

- A paquet sent by the gateway containing 15 lines starting with MT, where P is the adress.

- The response from the gateway containing 15 lines starting all with OK and where P is the containt at this adress.


My assumption is that the last line (adress 0900) contains the A/C serial n° (hidden)

in addition :


Now start playing ...

I connect my smartphone to the Hi-humo app and try to catch some commands between

In this case a very diffrent paquet is sent to the A/C containing 12 lines staring all with ST, P contains the adress followed by the value.

4 adress are missing and one (0007) is not only use in this message frame. I noticed that some adress are used several time in the same paquet and the adress sequence is also not the same.

If everything works well the A/C should asnwer
At this stage I noticed that the communication for this A/C unit is very similar to the one used and hacked by Florian in this project (thks to him). There are more containt, more lines in the paquet and probably at the end more function to manage.

One setp further !

I made some additionnal test with the IR remote control. Of course since the receiver is located directly inside the A/C housing the communication will not pass through the SPX-WFG01 and I'll not be able to get the content.
But the good news is that the  the A/C continues to send the ACK on his serial port so I was able to made some interesting comparisons.

... stay tuned !

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