Repository files navigation

This work is licensed under aCreative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

The purpose of this project, viaHomeSpan orESPHome, is to be able to control your Fuji-Electric Air Conditioning Indoor Unit fromHomeKit orHome Assistant.

This is an interface between a Fuji-Electric Indoor Unit (with 3-Wires Remote Controller) and an Atom Lite (ESP32 based) device.

This interface was inspired by the project in theUnreality's repo.

This is the first prototype I shared onHome Assistant Community.

The tested version, so calledAtom Lite, can be purchased on the offical site.

There is also a new version,AtomS3 Lite, available for purchase on the official site.

Pease note, I have not tested the Fuji-Atom Interface on the new AtomS3 Lite, I only notice that the power pins are unchanged and the pin-matching between the Atom Lite and the AtomS3 Lite is the following:

• G22 (Atom Lite) -> G5 (AtomS3 Lite)
• G19 (Atom Lite) -> G6 (AtomS3 Lite)

• Fuji_HK_V1_Rev2.0.zip

• Fuji_HK_V2_Rev1.5.zip

When the JLCPCB site prompts you to upload Gerber files, directly upload the "Fuji_HK_VX_RevX.X.zip" archive you have chosen.

There are two versions of the circuit:

• V1_Rev2.0 -> powers the Atom @3.3V on the appropriate pin
• V2_Rev1.5 -> powers the Atom @5V on the appropriate pin

Choose the one you prefer, there is no difference in the final operation.

I prefer to use V2_Rev1.5 to complain the Atom Lite specifications.

Before accessing any internal part of the Indoor Unit or Remote Controller, make sure that you turn off the power to the Indoor Unit via the breaker in your electrical panel.
If there is no dedicated switch for the Indoor Unit in your electrical panel, is strongly recommended to turn off the main breaker.

💡 You need to connect the Fuji-Atom Interface in parallel with Remote Controller 💡

You can connect the Fuji-Atom Interface in parallel to theterminal block of any Remote Controller or equally directly to theterminal block of the Indoor Unit where you will already find the 3-Wires Harness of the Remote Controller(s) already installed.

Fuji's indoor units can be controlled by a maximum of two Remote Controllers.
So, if you already have two Remote Controllers, you must disconnect one of them (preferably the Slave) in order to install the Fuji-Atom Interface.
Then, the Fuji-Atom Interface will replace one of the two Remote Controllers.

There are three possible configurations:

• Remote Controller = Master Unit --- & --- Atom = Slave Unit (Suggested)
  To do so, make sure the Atom isset via firmware to be aSlave Unit (If you use theUnreality's firmware, it willautomatically set itself as a Slave Unit).
  Also, make sure thatDIP-Switch 1-No.2 of the existing Remote Controller is set toOFF so that it assumes the role of theMaster Unit.

graph TD;    A(Indoor Unit)---B("Remote Controller 1 (Master)");    A---C("Atom (Slave)");

• Remote Controller = Slave Unit --- & --- Atom = Master Unit
  In this configuration you have to setDIP-Switch 1-No.2 of the exixting Remote Controller toON while you have to set the Atom via firmware to be the Master Unit (Not recommended becausea Slave Unit will not work in the absence of a Master Unit, so if the Atom dies you will not be able to control the Indoor Unit via Remote Controller).

graph TD;    A(Indoor Unit)---B("Atom (Master)");    A---C("Remote Controller 1 (Slave)");

• Remote Controller = Not present --- & --- Atom = Master Unit
  If you strangely do not have a Remote Controller, you only need to set the Atom via firmware to be the Master Unit.

graph TD;    A(Indoor Unit)---B("Atom (Master)");

Connect the wires in this way:

• Red (on Indoor Unit or Remote Controller) -> 12V (on Fuji-Atom Interface)
• White (on Indoor Unit or Remote Controller) -> LIN (on Fuji-Atom Interface)
• Black (on Indoor Unit or Remote Controller) -> GND (on Fuji-Atom Interface)

CompleteInstallation Manual of UTY-RNNUM Remote Controller (3-Wires)

In case a component is not available, replace it with one of equal characteristics.
("Description" column of the BoM)

Components of equal characteristics on the BoM can be found by typing the part number onOctopart.
("Manufacturer Code" column of the BoM)

As for the capacitors, do not get stuck on the choice of temperature coefficient on the BoM if you should not find it, but quietlychoose from these nine values: X5S X5R X5P X6S X6R X6P X7S X7R X7P.
(The scale is: from the "worst" X5S, to the best X7P).

🚫 Be careful, the two ICs (IC1 and U1) cannot be replaced because of different pins layout 🚫

Since the PCB is designed forSMT (Surface-Mount Technology),you need to ask the PCB manufacturer to provide you with thesolder paste stencil, you can find it under "SMT-Stencil".

Than you can easily follow this procedure:

1. Apply solder paste to the PCB using the solder paste stencil;
2. Place the components with tweezers (pay attention to components orientation where specified);
3. Heat the PCB around 150°-250°C (depends on the solder paste) with a hot air gun or a heating plate.

This procedure is much easier and safer if done by heated plate instead of hot air gun.

So basically, you will need three things:

• Heating Plate (also known as Reflow Station)
• Solder paste
• Tweezers

Here's acheap Heating Plate on AliExpress.