Excellent job Arnold, thanks a lot!
I have the same experience with the circuit. The original schematics did not work for me. With modifications (1) and (2), the circuit works OK. There are errors, but still OK for the purpose of decoding the data. I am too scared to do modification (3).
Did you try to connect the transmission part of the schema? Maybe the readability of P1P2 improves once we have the transmission part connected.
It works! I am able to read the data with Arduino Nano and your P1P2Serial, P1P2Monitor. The good news is that protocol data format is very similar. With some minor differences:
- Some packets are longer (400013, 400015)
- I have some additional packets (000016, 400016)
You can find my initial readings in this Excel file.
P1P2.zip (22.3 KB)
Each packet (I only did the data packets) has its own sheet in xls. My readings (hex) are in the 3rd column, GREEN means I have confirmed your readings. ORANGE means something new or different from your readings.
My next plans: connect Arduino (via USB/serial) to Raspberry running Node Red. Once I have the data in Node Red, it will be much easier for me to filter the data and detect changes to the data. Maybe there are easier ways to do that, but I am not a developer. Node Red is one of the few programming tools I am familiar with.
Oh and about my Daikin: Altherma LT EHVX08S26CB9W. Two heating zones (main, add). Main is used for floor heating, additional zone is for ceiling cooling. My unit is currently in “RT control” (thermostat control), weather dependent.