iot_ac

Archived as of 2023 March 2nd

Functionality of this project has been replaced with a Zigbee temperature sensor and a TuYa IR Remote flashed with ESPHome: infra/living-room-ac.yaml.

Control Midea split AC unit through Home Assistant with a Raspberry Pi.

Components

• Midea AC unit with R51M remote
• Raspberry Pi with 40-pin GPIO
• USB WiFi adapter for older Pis
• Anavi Infrared pHAT with HTU21D sensor
• Home Assistant
• MQTT broker of choice

To get started install the pHAT along with the sensor to the Pi. The IR leds should have line of sight of the split unit, but the signals can bounce off walls pretty good.

Installation

Preparing the SD card

Insert the SD card and find its ID with diskutil list then run prepare-sdcard.sh to install Raspbian on it:

./prepare-sdcard.sh /dev/disk3

Installing on the Pi

Designed to be used as an Ansible role included in a playbook. To install include in the requirements.yml like so:

collections:
  - name: git@github.com:andrasmaroy/iot_ac.git#/ansible
    type: git

And in the playbook file for the appropriate hosts:

- hosts: iot_ac
  collections:
    - andrasmaroy.iot_ac
  tasks:
    - import_role:
        name: iot_ac

Presented as a collection so that it can be installed directly from the ansible subfolder of this repo.

Configuration

The following Ansible vars are available for configuration:

mqtt_host (required): Hostname of the MQTT host to connect to

mqtt_port (default: 1883): Port to use for MQTT connection

mqtt_user (default: iot_ac): MQTT username

mqtt_password (required): MQTT password

Home Assistant

The way the code communicates with Home Assistant assumes that MQTT Discovery is enabled and presents as two sensors and a climate unit.

Decoding the remote

Details about decoding from Gabriel Oliveira

Decoding the remote

Decoding

Normal remotes (TV, Blu-Ray Players, etc...) send just one signal for each key pressed. However, A/C remotes need to display info about the A/C current state, which are stored in it and can be changed even if the A/C is out of reach. So the remote needs to send all parameters (temperature, current mode, fan speed, etc...) to avoid synchronization problems.

The code for Midea AC is (in hex):

0x s F s 0 t m t m

Second digit is always F, fourth digit is always 0. They MAY have something to do with fan direction and/or energy settings, as I didn't have the time to decode them yet.

1st and 3rd digits (s): Fan Speed

1 E - auto (on modes where fan speed can only be "auto" - auto, dry)
B 4 - Auto
9 6 - Low
5 A - Med
3 C - High

5th and 7th digits (t): Temperature

0 F - 17°C
1 E - 18°C
3 C - 19°C
2 D - 20°C
6 9 - 21°C
7 8 - 22°C
5 A - 23°C
4 B - 24°C
C 3 - 25°C
D 2 - 26°C
9 6 - 27°C
8 7 - 28°C
A 5 - 29°C
B 4 - 30°C

6th and 8th digits (m): Mode

8 7 - Auto
0 F - Cool
4 B - Dry/Fan (Fan Speed tells them apart)
C 3 - Heat

Examples:

17°C, cool, low
0x9F6000FF

23°C, heat, auto
0xBF405CA3

Ackowledgements

• Gabriel Oliveira and NikolaV for the Midea Lirc configs
• Patch for Lirc for Raspberry Pi