esphome-docs/devices/sonoff_t3_eu_3gang_v1.0.yaml

esphome:
  name: <NAME_OF_NODE>
  platform: ESP8266
  board: esp01_1m
  # Automation turning on the blue status LED once T3 is booted up
  on_boot:
    priority: -10
    then:
      - light.turn_on: blue_led_light

wifi:
  ssid: <YOUR_SSID>
  password: <YOUR_PASSWORD>

# Enable logging
logger:

# Enable Home Assistant API
api:

ota:

binary_sensor:
  - platform: gpio
    pin:
      number: GPIO0
      mode:
        input: true
        pullup: true
      inverted: true
    name: "Sonoff T3 EU 3 Gang Touchpad 1"
    on_press:
      - switch.toggle: relay_1
  - platform: gpio
    pin:
      number: GPIO9
      mode:
        input: true
        pullup: true
      inverted: true
    name: "Sonoff T3 EU 3 Gang Touchpad 2"
    on_press:
      - switch.toggle: relay_2
  - platform: gpio
    pin:
      number: GPIO10
      mode:
        input: true
        pullup: true
      inverted: true
    name: "Sonoff T3 EU 3 Gang Touchpad 3"
    on_press:
      - switch.toggle: relay_3
  - platform: status
    name: "Sonoff T3 EU 3 Gang Status"

switch:
  - platform: gpio
    name: "Sonoff T3 EU 3 Gang Relay 1"
    pin: GPIO12
    id: relay_1
  - platform: gpio
    name: "Sonoff T3 EU 3 Gang Relay 2"
    pin: GPIO5
    id: relay_2
  - platform: gpio
    name: "Sonoff T3 EU 3 Gang Relay 3"
    pin: GPIO4
    id: relay_3

output:
  # Register the blue LED as a dimmable output ....
  - platform: esp8266_pwm
    id: blue_led
    pin: GPIO13
    inverted: true

light:
  # ... and then make a light out of it.
  - platform: monochromatic
    name: "Sonoff T3 EU 3 Gang Blue LED"
    output: blue_led
    internal: true
    id: blue_led_light