Add this blueprint: https://my.home-assistant.io/redirect/blueprint_import/?blueprint_url=https%3A%2F%2Fgist.githubusercontent.com%2Ftjhorner%2F51fb1d9549e7b12c5b1eddcd23f89604%2Fraw%2Fcc2f98d574455f95393addf683a733ccb945d9dc%2Fglucose-lights.yaml

glucose-lights.yaml

blueprint:
  name: Glucose Lights
  description: Change light color on a gradient of green to red based on glucose value
  author: TJ Horner (@tjhorner)
  domain: automation
  input:
    glucose_sensor:
      name: Glucose Value Sensor
      selector:
        entity:
          filter:
            domain: sensor
            device_class: [ blood_glucose_concentration ]
    target_lights:
      name: Target Lights
      description: The lights to update when glucose value changes. (Must support RGB color.)
      selector:
        entity:
          multiple: true
          filter:
            domain: light
    low_value:
      name: Low Threshold
      description: |
        Readings above but close to this value will make the lights greener.
        Readings below this value will make the lights pure red.
      default: 70
      selector:
        number:
          min: 0
          max: 300
    high_value:
      name: High Threshold
      description: |
        Readings below but close to this value will make the lights redder.
        Readings above this value will make the lights red.
      default: 180
      selector:
        number:
          min: 0
          max: 300
mode: single
triggers:
  - trigger: state
    entity_id: !input glucose_sensor
  - trigger: state
    entity_id: !input target_lights
    from: "off"
    to: "on"
conditions:
  - condition: state
    entity_id: !input target_lights
    state: "on"
actions:
  - variables:
      glucose_sensor_id: !input glucose_sensor
      high_thresh: !input high_value
      low_thresh: !input low_value
  - variables:
      color: |
        {% set glucose = states(glucose_sensor_id) | int %}
        {% set pct = (1 - ((glucose - low_thresh) / (high_thresh - low_thresh))) * 100 %}
        {% set r, g, b = 0, 0, 0 %}

        {% if (pct > 100) or (pct < 0) %}
          {% set r = 255 %}
        {% elif (pct <= 51) %}
          {% set r = 255 %}
          {% set g = (5.0 * pct) | round | int %}
        {% else %}
          {% set g = 255 %}
          {% set r = (505 - 4.89 * pct) | round | int %}
        {% endif %}
        {{ [ r, g, b ] }}
  - action: light.turn_on
    data:
      rgb_color: "{{ color }}"
    target:
      entity_id: !input target_lights