ESPhome example for smart light switches controlling smart lights via HASS that degrade to dumb mode automatically

00-README.md

Posting by request from https://www.reddit.com/r/homeassistant/comments/1hufw9c/i_got_my_shellys_to_keep_working_in_case_of_a/

My ESPHome file is higly modularized with a lot of other functionality that is not relevant right now, so here's an extract of the relevant bits. It's a bit more verbose than usual because it's the output of ESPHome validation process, which dumps the processed YAML after "expanding" it.

Context:

• light switch is a Shelly, but not really relevant — any ESP relay with a button would work
• connected to the relay are smart lights talking Zigbee
• when switch is "smart", relay remains on all the time and switch talks to HASS that turns on/off the light accordingly
• when switch is "dumb", it takes control by turning the relay on/off instead
  • this requires that the light is configured to turn on when power is cut and back on, i.e., acts as a dumb light
• I have installed springs behind every light switch, so they act as momentary switches instead of flipping
  • one click toggles the light on/off
  • multiple clicks or holding the button does other stuff (omitted here for brevity)

How it works:

• there is a switch component that controls if the relay is in dumb mode or not
  • when disconnected from Home Assistant, dumb mode is assumed automatically irrespective of the state of this switch
• Shelly has a multi-click handler attached to the button that calls the relevant scripts (for brevity I included only button_click_single)
• when not in dumb mode:
  • send event to home assistant indicating which light to turn on
  • wait to see if light changes state
  • if light has not changed state, assume there's something wrong in HASS side (misconfiguration, Zigbee is not working, etc.):
    • when turning on the light, toggle the relay off and back on to force it to turn on (actually it is done twice in quick succession because this makes Philips Hue lights revert to maximum brightness)
    • when turning off the light, just turn off the relay
    • enter dumb mode automatically
• when in dumb mode, just toggle the relay
• Home Assistant notices any Shelly changing to unavailable or dumb mode and will:
  • notify me so I know something's off
  • turn off the dumb mode to make the light switch smart again, if it concludes that it was due to a temporary disconnection

Other implementation notes:

• the functions in C act as a glorified "macro", so it's shorter to refer to them than repeating the same logic everywhere
• state of the light in ESPhome side is text and not boolean so it can differentiate a light being off and being unavailable
  • if the light itself is offline for some reason (let's say Zigbee network down), it will make Shelly enter dumb mode

The result of this is that a single press of the light switch will always work, and will always succeed in toggling the light even if:

• the Wi-Fi is down
• Home Assistant is down
• Zigbee network is down
• everything is up but a misconfiguration is preventing the click on the switch from "reaching" the right light
• the smart light has been substituted with a dumb light

01-functions.h

bool is_light_on() {
  bool relay_on = id(relay).state;
  if(id(light_dumb).state) {
    return relay_on;
  } else {
    return relay_on
      && (global_api_server->is_connected()
      && id(light_entity_hass).state == "on");
  }
}

bool is_light_off() {
  bool relay_off = !id(relay).state;
  if(id(light_dumb).state) {
    return relay_off;
  } else {
    return relay_off
      || (
        global_api_server->is_connected()
        && id(light_entity_hass).state == "off"
      );
  }
}

bool should_turn_light_on() {
  if(is_light_on()) {
    return false;
  } else if(is_light_off()) {
    return true;
  } else {
    // State is intederminate, turn light off in that case
    // since it's marginaly better than a light being stuck
    // in the on state.
    return false;
  }
}

02-switch.yaml

esphome:
  includes:
  - functions.h

binary_sensor:
- platform: template
  id: light_state
  name: light state
  lambda: !lambda |-
    return is_light_on();
  icon: mdi:lightbulb-outline
  entity_category: diagnostic
  disabled_by_default: true

switch:
- platform: template
  id: light_dumb
  name: light dumb mode
  icon: mdi:head-remove
  entity_category: config
  optimistic: true
  restore_mode: RESTORE_DEFAULT_OFF
  disabled_by_default: false
  assumed_state: false

text_sensor:
- platform: homeassistant
  id: light_entity_hass
  entity_id: light.ceiling
  disabled_by_default: false
  internal: true
  name: light_entity_hass

script:

- id: button_click_single
  then:
  - if:
      condition:
        lambda: !lambda |-
          return should_turn_light_on();
      then:
      - logger.log:
          format: light was off, attempting to turn on
      - script.execute:
          id: light_on
      - script.wait:
          id: light_on
      else:
      - logger.log:
          format: light was on, attempting to turn off
      - script.execute:
          id: light_off
      - script.wait:
          id: light_off

- id: light_on
  then:
  - script.execute:
      id: relay_on_and_wait_light
  - script.wait:
      id: relay_on_and_wait_light
  - if:
      condition:
        and:
        - switch.is_off:
            id: light_dumb
        - api.connected: {}
      then:
      - logger.log:
          format: publishing event to HASS
      - homeassistant.event:
          event: esphome.light_switch
          data:
            action: toggle_on
            light: light.ceiling
      - script.execute:
          id: wait_light_on
      - script.wait:
          id: wait_light_on
      - if:
          condition:
            lambda: !lambda |-
              return is_light_on();
          else:
          - logger.log:
              format: light did not turn on, cyling relay and enabling dumb mode
          - switch.turn_off:
              id: relay
          - delay: 500ms
          - switch.turn_on:
              id: relay
          - delay: 500ms
          - switch.turn_off:
              id: relay
          - delay: 500ms
          - script.execute:
              id: relay_on_and_wait_light
          - script.wait:
              id: relay_on_and_wait_light
          - switch.turn_on:
              id: light_dumb
      else:
      - logger.log:
          format: HASS offline, cannot request to turn light on

- id: light_off
  then:
  - if:
      condition:
        and:
        - switch.is_off:
            id: relay
      then:
      - logger.log:
          format: relay is off, nothing to do
      - script.stop:
          id: light_off
  - if:
      condition:
        and:
        - switch.is_off:
            id: light_dumb
        - api.connected: {}
      then:
      - logger.log:
          format: publishing event to HASS
      - homeassistant.event:
          event: esphome.light_switch
          data:
            action: toggle_off
            light: light.ceiling
      - script.execute:
          id: wait_light_off
      - script.wait:
          id: wait_light_off
      - if:
          condition:
            lambda: !lambda |-
              return is_light_off();
          then:
          - script.stop:
              id: light_off
          else:
          - logger.log:
              format: light not turning off, will turn off relay and enable dumb mode
      else:
      - logger.log:
          format: HASS offline, will turn off relay instead
  - logger.log:
      format: turning off relay
  - switch.turn_off:
      id: relay
  - switch.turn_on:
      id: light_dumb

- id: relay_on_and_wait_light
  then:
  - if:
      condition:
        switch.is_on:
          id: relay
      then:
      - script.stop:
          id: relay_on_and_wait_light
  - logger.log:
      format: relay is off, turning on relay
  - switch.turn_on:
      id: relay
  - wait_until:
      condition:
        switch.is_on:
          id: relay
      timeout: 1s
  - logger.log:
      format: relay turned on
  - script.execute:
      id: wait_light_on
  - script.wait:
      id: wait_light_on

- id: wait_light_on
  then:
  - logger.log:
      format: waiting for light to report that is on
  - wait_until:
      timeout: 5s
      condition:
        lambda: !lambda |-
          return is_light_on();
  - if:
      condition:
        switch.is_off:
          id: relay
      then:
      - logger.log:
          format: light off, relay is off
      - script.stop:
          id: wait_light_on
  - if:
      condition:
        api.connected: {}
      else:
      - logger.log:
          format: light state unknown, disconnected from HASS
      - script.stop:
          id: wait_light_on
  - if:
      condition:
        lambda: !lambda |-
          return is_light_on();
      then:
      - logger.log:
          format: light reported on
      else:
      - logger.log:
          format: gave up waiting for light to report on

- id: wait_light_off
  then:
  - logger.log:
      format: waiting for light to report that is off
  - wait_until:
      timeout: 5s
      condition:
        lambda: !lambda |-
          return is_light_off();
  - if:
      condition:
        switch.is_off:
          id: relay
      then:
      - logger.log:
          format: light off, relay is off
      - script.stop:
          id: wait_light_on
  - if:
      condition:
        api.connected: {}
      else:
      - logger.log:
          format: not connected to HASS, light state unknown
      - script.stop:
          id: wait_light_on
  - if:
      condition:
        lambda: !lambda |-
          return is_light_off();
      then:
      - logger.log:
          format: light reported that is off
      else:
      - logger.log:
          format: gave up waiting for light to report off