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Arnold-n / P1P2MQTT

Monitor and control Daikin/Rotex (hybrid/Altherma) heat pumps via the 2-wire P1/P2 thermostat interface with an ATmega328P, ESP8266, and electronics. The P1P2Serial library and P1P2Monitor program perform low-level bus operation, the P1P2-bridge-esp8266 program interprets data from/to MQTT supporting Home Assistant MQTT discovery. P1P2Serial may also be used for other Japanese Home Bus System based standards: DIII-NET (F1/F2) bus, Mitsubishi M-Net bus, Toshiba TCC-Link, Hitachi H-link, Panasonic/Sanyo SIII-Net, Haier, York, and others.
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Link Between outside and inside units #127

Open x3oo opened 2 months ago

x3oo commented 2 months ago

Hi does anybody know if the link between the outside and inside units use the same protocoll? Usually many ACs only use one wire for communication between those.

Arnold-n commented 2 months ago

Some AC units use 2-wire F1/F2 which is electrically the same as P1/P2, but logically different. And F1/F2 may not provide bus power.

Other units use a one-wire protocol, this may be unsafe to touch, and which is definitely different from P1/P2.

x3oo commented 2 months ago

For context: Many ACs are well capable of heating up your water based heating system, if only you could attach a heat exchanger as an indoorunit. Since many people already do have AC Units it would be quite easy to connect them to the heating system if only you could communicate with the Outside unit.

Another application would be to build some specialised systems for example to heat your RV and warm water.

Also prices for Waterunits seem to be quite high compared to Air/Air Units.

x3oo commented 2 months ago

Some AC units use 2-wire F1/F2 which is electrically the same as P1/P2, but logically different. And F1/F2 may not provide bus power.

Other units use a one-wire protocol, this may be unsafe to touch, and which is definitely different from P1/P2.

Daikin Emura uses only one wire to my knowledge.

x3oo commented 2 months ago

Some AC units use 2-wire F1/F2 which is electrically the same as P1/P2, but logically different. And F1/F2 may not provide bus power.

Logically only means that there are other messages or that it's another protocol?

Arnold-n commented 2 months ago

It's also packet-based, but with different packet lenghts and (unknown) content.

x3oo commented 2 months ago

It's also packet-based, but with different packet lenghts and (unknown) content.

how hard would it be for a motivated human being to decode?

Arnold-n commented 2 months ago

Certainly doable!