If you’re integrating a Daikin ducted air-conditioning system with Home Assistant, you may have come across the Faikin Ninja, an interface for communicating with compatible Daikin systems over the P1/P2 bus.
Could a zone controller also communicate with the air conditioner?
At TekOnline, we’re investigating whether our V3 Smart Zone Controller could eventually work with compatible Daikin systems through P1/P2. This is an early feasibility investigation. We have not confirmed support for any Daikin model, including the FDYAN85AV1.
We’re especially interested in feedback from installers, Home Assistant users and developers who have worked with Daikin’s communication protocols.
Separate parts of a ducted smart-home setup
A typical smart ducted installation may use separate components for separate jobs:
- A Daikin interface, such as Faikin Ninja, to monitor or control a compatible air conditioner.
- A zone controller to operate motorised dampers.
- Home Assistant to coordinate devices and automations.
Our TekOnline V3 controller operates compatible motorised dampers and supports estimated proportional positioning based on calibrated travel times. That does not currently make it an air-conditioner interface. The question is whether it could eventually take on both roles.
What is Daikin P1/P2?
P1/P2 is a two-wire connection used by many Daikin systems for communication with a wired controller. Its physical layer is based on the Japanese Home Bus System (HBS), a low-speed, half-duplex signalling system. The bus carries a DC voltage, so it is not a UART connection and must not be wired directly to a microcontroller’s UART pins.
Community projects such as P1P2MQTT have documented the bus and demonstrated monitoring and control on supported equipment. Depending on the system and implementation, functions can include power, operating mode, target temperature, fan speed and system status. Compatibility and available functions vary by model.
Hardware options described by the community include the MAX22088 and MM1192. They are not interchangeable in every respect: for example, the MAX22088-based P1P2MQTT interface can provide power from the bus, while the MM1192 can read and write but does not provide bus power. Any design would need an appropriate transceiver and carefully designed interface circuitry.
Could the TekOnline V3 communicate with P1/P2?
The V3 is built around an ESP32 and provides a six-pin 3.3 V TTL UART expansion header. The header includes ground, 3.3 V, TX, RX, a direction-enable pin and an auxiliary 5 V supply. It is an expansion interface, not a built-in P1/P2 port.
Connecting the V3 to a Daikin system would require a suitable HBS transceiver and interface circuit between the P1/P2 bus and the controller. It would also require firmware to implement the communication protocol and meet its timing requirements. The UART pins are 3.3 V logic only, and the expansion header shares the controller’s USB programming UART.
We have not yet confirmed whether the V3 hardware and firmware can support this reliably. This is more involved than connecting the two bus wires to the controller.
What about the Daikin FDYAN85AV1?
The FDYAN85AV1 is one system that prompted this investigation. Reverse-engineering work covers some Daikin FDY and FDYQ equipment, but we have not confirmed that it applies to the FDYAN85AV1.
P1/P2 compatibility is model-specific. We’re looking for reports tied to exact indoor-unit models, the wired controller in use, and observed results. That evidence will help establish which systems have actually been tested and what functions are available.
The longer-term idea: zoning and air conditioning together
An integrated Home Assistant setup could potentially coordinate:
- Individual zone dampers and estimated damper positions.
- Air-conditioning power and operating modes.
- Temperature setpoints and fan speed.
- Zone changes with the air conditioner’s operation.
This is an investigation, not an advertised V3 feature. Compatibility, electrical design, safety and reliability would need to be established before we could consider a release.
We welcome your experience
Have you used a Faikin Ninja, P1P2MQTT or another third-party Daikin interface? We’d particularly like to hear from anyone who:
- Has tested P1/P2 on a Daikin FDYAN or FDY-series system. Please include the exact model and wired controller.
- Has worked with MAX22088 or MM1192 transceivers.
- Has implemented P1/P2 communication on an ESP32.
- Would find an integrated Daikin and motorised-zone controller useful.
Compatibility reports, test results and technical suggestions are welcome. Contact us through TekOnline.
TekOnline is an independent smart HVAC controller developer. This research is not affiliated with or endorsed by Daikin or the developers of Faikin Ninja.