ESPHome-based Air Conditioner

Replace your window air conditioner manual controls with a relay board, connected to an ESP8266-based microcontroller running ESPHome.

Prerequisites

This project assumes that you have Home Assistant running locally, with the ESPHome project installed and running. The author recommends a Raspberry Pi runing HassIO with the ESPHome add-on installed.

Hardware

This firmware has been developed and tested with the following hardware:

• Wemos D1 Mini R2 microcontroller (other ESP8266 boards may also work)
• SSD1306 I²C OLED display, 128x64
• HTU21D I²C temperature and humidity sensor
• BH1750 I²C light sensor (optional)
• Generic 2 or 3 relay module, active low! (meaning it will activate the relay when the GPIO is at 0V)
  • For units with dual fan speed, you will need 3 relays to control compressor, fan state, and fan speed
  • For units with only compressor and fan, a dual relay module will suffice.
• 8-LED WS2812B ring module
• Rotary Encoder

Installation

For this document purpose, we will assume the device ID is set to airconditioner1 in your setup.

Home Assistant

This firmware is designed to run independently of Home Assistant, but with strong integration using the native ESPHome API. There are two basic control input elements expected by the firmware, for setting the desired temperature and the operation mode.

You will need to add the following configuration.

input_number:
  airconditioner1_temp:
    name: Air Conditioner Temp
    min: 19                       # Modify these values as appropriate for your desired operation.
    max: 27
    step: 0.5

input_select:
  airconditioner1_mode:
    name: Air Conditioner Mode
    options:                      # These are the default operation modes available
      - "off"
      - "auto"
      - "cool"
      - "fan_only"
    initial: "off"
    icon: mdi:snowflake

ESP8266

Download or clone the repository, and copy the files into your /config/esphome directory on your Home Assistant instance. You can optionally exclude some of the files in this repository that are not required for operation (e.g. README.md).

You will need to make the following connections:

Wemos D1 Mini	SSD1306	HTU21D	BH1750	WS2812B	Relay1 (Fan Enable)	Relay2 (Compressor)	Relay3 (Fan Speed)	Relay VCC	Relay GND
3V3	VCC	VCC	VCC
5V				VCC				VCC
D1	SDA	SDA	SDA
D2	SCL	SCL	SCL
D3				D IN
D5					IN
D6						IN
D7							IN
GND	GND	GND	GND	GND					GND

You will also need to create a secrets.yaml file inside your /config/esphome directory, with the following definitions:

ssid: {{your_network_ssid}}
wifi_password: {{wifi_password}}

Once you have the configurations set up for both Home Assistant and ESPHome, you can use the ESP Home interface to upload to the device.