FakeA41

Tasmota enabled DIY Replacement for brp069a41 wifi modules on Daikin A/C units.

USE THIS SOFTWARE AND THE HARDWARE DESCRIBED AT YOUR OWN RISK
I'm not an engineer, it may contains flaws that can cause any kind of damage.

Hardware needed:

Voltage regulator from about 12V to 5V
Level shifter 5V-3.3V
ESP32 based board (tested on Wemos Lolin D32 Pro, ESP32-C3-DEVKITC-02, Wemos Lolin32 Lite)

NB the unit has a 5V pin, but it doesn't seem to be able to supply enough current to run the ESP. See this issue.

The A/C unit plug is as follow (at least on my unit, check yours before connecting anything):

Circuit:

Connect 12V and GND to the input of the voltage regulator
Connect TX and RX via the level shifter to pin GPIO_RX and GPIO_TX of the board (as defined below).
Power the board (if it have a 5V power input) and the HV side of the level shifter with the output of the voltage regulator.
Power the LV side of the level shifter with the 3.3 pin of the ESP32 board.

Here a couple of example boards:

example boards

Here's a smaller board with a Wemos S2 Mini:

Flash the board with tasmota firmware for ESP32.
Setup tasmota as per standard (wifi, mqtt etc)
Edit this Berry script so that GPIO_RX and GPIO_TX match your setup
Go to the file manager, upload the script and rename it "autoexec.be" to have it run at every reboot.

On tasmota, you'll be able to control the A/C unit with a JSON command like:

DaikinCtrl {"active":true, "mode":"COOL", "fan":"NIGHT", "temperature":20, "swingH":true, "swingV":false }

Also, two sensors will be exposed:

(your ESP board will also probably have an internal temperature sensor that will be exposed by Tasmota)

This software is based on the reverse engineering work of @maser777 and @relghuar at OpenEnergyMonitor.

Thanks to you and all the other hackers!