ESPHome recipe using SonOff S31 as an external Home Assistant Watchdog.

..ESPHome - homeassistant API watchdog readme.md

This watchdog relies on the native API connection reboot_timeout, to do the work. On Boot the ESP the .api-watchdog.yaml toggles off the switch’s relay supplying power to the Home Assistant for the specified time, ensuring the relay will properly power cycle the device. Additionally, the package is setting up metering sensors for testing and monitoring purposes.

Notes:

1. This project has multiple files arranged as packages for modular setup of hardware, network and features.

   • homeassistant-watchdog.yaml - Top level file, that combines the below.
     • .api-watchdog.yaml - Abstracting particulars for the watchdog.
     • .network.yaml - Abstracting network setup.
     • .sonoff-s31.yaml - Abstracting hardware setup.

2. The . dot prefix hides the files from ESPHome's HomeAssistant integration. The same can be done with the main file. As to prevent it from getting updated by the "UPDATE ALL" command. Which would result in a premature power cycle for the Home Assistant. Given it likely would not be the last in the upgrade order.

3. The off_delay should be specified to a sufficiently long enough time, to ensure all dependent devices power cycle and not just the Rpi. Such as any USB-SSD devices and any other USB devices. The default is set to 5s.

.api-watchdog.yaml

# ESPHome package for watchdog monitoring of remote device's API connection.
# Required: relay, should be defined by main or other yaml.
# Optional: api_loss_threshold, can be defined by main, else defaults to 16m.
#
# example use:
#    esphome_name: homeassistant-watchdog
#    friendly_name: HomeAssistant Watchdog
#    packages:
#      board: !include .sonoff-s31.yaml
#      network: !include .network.yaml
#      watchdog: !include .api-watchdog.yaml
#
# recommended hardware:
# https://www.amazon.com/Sonoff-S31-SONOFF-Plug-White/dp/B08TNF4835

substitutions:
  # Number of minutes without HA connection to trigger relay.
  # Caution - needs to be longer than startup of HA.
  # Other reboots default to 15, e.i WiFi. So lets give them a chance first.
  api_loss_threshold: "16min" # The default is 15 min
  off_delay: "5s" # Off time of relay, Select a time as to avoid "brown-out".
                  # Note this is time for all hardware. Rpi and SSD, etc...

esphome:
  on_boot:
  - then:
    - switch.turn_off:
        id: relay
    - delay: ${off_delay}
    - switch.turn_on:
        id: relay

# Enable Home Assistant API.
api:
  # Watchdog of ESP device itself for missing HomeAssistant's API connection.
  # Caution - needs to be longer than startup of HA
  reboot_timeout: ${api_loss_threshold} # 15min is default
  on_client_connected:
    - logger.log: API got a connection!
  on_client_disconnected:
    # Note - This is triggered on any disconnect, regardless of muliple API
    # connections. Note the api.connected condition is not valid here.
    # See below binary_sensor "status" shows when there is any API connections.
    - logger.log: API lost a connection!

switch:
  # The default is ALWAYS_OFF
  # on_boot or button will toggle the specified time period.
  - id: !extend relay
    restore_mode: ALWAYS_OFF

binary_sensor:
  # Remove any/all prior button actions as dict.
  - id: !extend button
    on_press: {}
  # Then create a new action guarenteed to turn back on.
  - id: !extend button
    on_press:
    - then:
      - switch.turn_off: relay
      - delay: ${off_delay}
      - switch.turn_on: relay

wifi:
  # Watchdog of ESP device itself for missing Wi-Fi.
  # Caution - needs to be longer than startup of network equipment
  reboot_timeout: 15min # 15min is default

sensor:
  # Uptime component is helpful for monitoring watchdog timeouts events.
  # This can be compared to HA's uptime, for problem solving.
  - platform: uptime
    name: Uptime
    id: esp_uptime

.network.yaml

# ESPHome Package for basic network setup of remote device
# example use:
#    substitutions:
#      esphome_name: living-room
#    packages:
#      board: !include .shellyplus1.yaml
#      network: !include .network.yaml

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password
  domain: .lan # My network uses this domain, yours may vary.

  ap:
    ssid: ${esphome_name}
    password: !secret wifi_password

captive_portal:

web_server:
  port: 80
  auth:
    username: !secret web_server_username
    password: !secret web_server_password

api:
  encryption:
    key: !secret api_encryption_key

ota:
  password: !secret ota_password

sensor:
  - platform: wifi_signal
    name: "WiFi Signal"
    # update_interval: 60s # default is 60s

binary_sensor:
  - platform: status
    name: "API/MQTT Connection"
    id: apimqtt_connection

.sonoff-s31.yaml

# ESPHome Package for hardware setup of Shelly Plus 1
# example use:
#    substitutions:
#      esphome_name: living-room
#      friendly_name: Living Room
#    packages:
#      board: !include .sonoff-s31.yaml
#      network: !include .network.yaml

substitutions:
  model_name: "Sonoff S31"

esphome:
  name: ${esphome_name}
  friendly_name: ${friendly_name}

esp8266:
  board: esp01_1m

logger:
  baud_rate: 0 # (UART logging interferes with cse7766)

uart:
  rx_pin: RX
  baud_rate: 4800

switch:
  - platform: gpio
    name: "${model_name} Relay"
    pin: GPIO12
    id: relay
    restore_mode: ALWAYS_OFF # The default is ALWAYS_OFF

binary_sensor:
  - platform: gpio
    pin:
      number: GPIO0
      mode: INPUT_PULLUP
      inverted: True
    name: "${model_name} Button"
    id: button
    on_press:
      - switch.toggle: relay

sensor:
  - platform: wifi_signal
    name: "${model_name} WiFi Signal"
    update_interval: 60s
  - platform: cse7766
    current:
      name: "${model_name} Current"
      accuracy_decimals: 1
    voltage:
      name: "${model_name} Voltage"
      accuracy_decimals: 1
    power:
      name: "${model_name} Power"
      accuracy_decimals: 1
      id: my_power
  - platform: total_daily_energy
    name: "${model_name} Daily Energy"
    power_id: my_power

time:
  - platform: sntp
    id: my_time

status_led:
  pin:
    number: GPIO13
    inverted: True

homeassistant-watchdog.yaml

substitutions:
  esphome_name: homeassistant-watchdog
  friendly_name: HomeAssistant Watchdog
  api_loss_threshold: "17min" # The default is 15 min

packages:
  board: !include .sonoff-s31.yaml
  network: !include .network.yaml
  wathdog: !include .api-watchdog.yaml

logger:
  level: VERBOSE
#wifi:
#  use_address: 192.168.20.?

Added "off_relay" delay to control proper off time as a managed variable. It is possible that reboot toggled power supply faster than supplies capacitors drain time.

Added to Readme