esphome-docs/devices/sonoff_s20.yaml

esphome:
  name: <NAME_OF_NODE>
  platform: ESP8266
  board: esp8285
  arduino_version: 2.4.2

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

api:

logger:

ota:

binary_sensor:
- platform: gpio
  pin:
    number: GPIO0
    mode:
      input: true
      pullup: true
    inverted: true
  name: "Sonoff S20 Button"
  on_press:
    - switch.toggle: relay
- platform: status
  name: "Sonoff S20 Status"


switch:
- platform: gpio
  name: "Sonoff S20 Relay"
  pin: GPIO12
  id: relay

output:
- platform: esp8266_pwm
  id: s20_green_led
  pin: GPIO13
  inverted: true

light:
- platform: monochromatic
  name: "Sonoff S20 Green LED"
  output: s20_green_led