Finite State Machine Sensor

Creates sensors who's state is backed by a Finite State Machine and a corresponding action that is used to trigger state changes.

Installation

Configuration

Currently configured using a JSON schema that is very close to Node Red's Finite State Machine

A special timeout trigger is supported for time-based automatic transitions.

Example Config

Tracks the state of a dryer starting up, running, and stopping. The automation sends above, below, and middle triggers based on the dryer's power consumption. Automatic transitions happen from STARTING to RUNNING after 1 second, from STOPPING to DONE after 2 minutes, and from DONE to IDLE after 15 seconds.

{
  "state": {
    "status": "IDLE"
  },
  "transitions": {
    "IDLE": {
      "above": "STARTING"
    },
    "STARTING": {
      "timeout": { "after": 1, "to": "RUNNING" },
      "below": "IDLE"
    },
    "RUNNING": {
      "below": "STOPPING"
    },
    "STOPPING": {
      "timeout": { "after": 120, "to": "DONE" },
      "above": "RUNNING",
      "middle": "RUNNING"
    },
    "DONE": {
      "timeout": { "after": 15, "to": "IDLE" }
    }
  }
}

Example Automation

Uses the FSM above, configured as sensor.dryer_state. Triggers are a faux drier power meter input_number.dryer_power and the FSM sensor when it transitions to the DONE state where we want to take an action.

The automation uses the state_machine.trigger action to send triggers to the sensor.dryer_state state machine entity based on the dryer's current power.

When the state machine eventually cycles to DONE that trigger results in a notification being sent.

alias: "!Laundry: Dryer Notifier"
description: ""
trigger:
  - platform: state
    entity_id:
      - sensor.dryer_state
    to: DONE
    id: DRYER_DONE
  - platform: numeric_state
    entity_id: switch.dryer_plug_switch
    above: 200
    id: FSM:above
  - platform: numeric_state
    entity_id: switch.dryer_plug_switch
    id: FSM:below
    below: 20
  - platform: numeric_state
    entity_id: switch.dryer_plug_switch
    id: FSM:middle
    below: 200
    above: 20
condition: []
action:
  - choose:
      - conditions:
          - condition: template
            alias: FSM Event
            value_template: |
              {{trigger.id.startswith('FSM:')}}
        sequence:
          - service: state_machine.trigger
            data:
              trigger: "{{trigger.id[4:]}}"
            target:
              entity_id: sensor.dryer_state
      - conditions:
          - condition: trigger
            id: DRYER_DONE
        sequence:
          - service: notify.iq_notify_parents
            data:
              message: >-
                Dryer is Done{{'<br>Washer Is Still Running' if
                states('sensor.washer_state') not in ['DONE', 'IDLE'] else ''}}
              title: Laundry
              data:
                mode: only_home_then_away
mode: queued
max: 10

Related Software

hasmtools

Hasmtools is a small python utility to visualize the state machine and convert the JSON configuration to/from YAML, started as a simple proof of concept. Code and examples are available on GitHub and the package can be found on PyPI.