Configuration for Sonoff S31 flashed with ESPHome

s31.yaml

esphome:
  name: s31-1
  friendly_name: s31-1

esp8266:
  board: esp01_1m
  early_pin_init: False  # Mitigate relay flipping on reboot.

# Disable logging (UART is used by cse7766 power sensor.)
logger:
  baud_rate: 0

# Enable Home Assistant API
api:
  encryption:
    key: "<redacted>"

ota:
  - platform: esphome
    password: "<redacted>"

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "S31-1 Fallback Hotspot"
    password: "<redacted>"

captive_portal:

# --- Config for smart switch operation ---
switch:
  - platform: gpio
    name: "relay"
    pin: GPIO12
    id: relay
    restore_mode: RESTORE_DEFAULT_OFF # Modify for your use case

binary_sensor:
  - platform: gpio
    pin:
      number: GPIO0
      mode: INPUT_PULLUP
      inverted: True
    name: "button"
    on_press:
      - switch.toggle: relay  # Switch always operates the relay

  - platform: status
    name: "status"

status_led:
  pin:
    number: GPIO13
    inverted: True

# --- Config for power monitoring ---
uart:
  rx_pin: RX
  baud_rate: 4800
  parity: EVEN

sensor:
  - platform: cse7766
    current:
      name: "current"
      accuracy_decimals: 2
      filters:
        throttle_average: 60s
    voltage:
      name: "voltage"
      accuracy_decimals: 0
      filters:
        throttle_average: 60s
    power:
      name: "power"
      accuracy_decimals: 1
      id: power
      filters:
        throttle_average: 60s

  - platform: integration
    name: "energy"
    sensor: power
    time_unit: h
    state_class: measurement
    unit_of_measurement: kWh
    filters:
      - multiply: 0.001

  - platform: wifi_signal
    name: "wifi_signal"
    update_interval: 60s