Sensor to output if date is odd or even

Configuration
1

I am trying to create a sensor that updates if the current date is odd or even. So far i have it working as per the code below but it is not live, it only updates when the configuration files are loaded… i guess thats how now() works… I have a time_date sensor set up but need help on adding it to my code.

# Monitor if date is odd or even
- platform: template
  sensors:
    odd_even:
      friendly_name: "Date Odd or Even?"
      value_template: >-
        {% if (now().strftime("%-d") | int % 2) == 0 %}
        Even
        {% else %}
        Odd
        {% endif %}
2

Since your template doesn’t have any entities it is never updated. You either need to assign the template an entity that changes appropriately, like sensor.date, or use an automation to force it to update. The docs describe how to do this: https://www.home-assistant.io/components/sensor.template/#working-without-entities

3

I have something fairly similar, try adding the entity as mentioned above.

# Monitor if date is odd or even
- platform: template
  sensors:
    odd_even:
      friendly_name: "Date Odd or Even?"
      value_template: >-
        {% if (now().strftime("%-d") | int % 2) == 0 %}
        Even
        {% else %}
        Odd
        {% endif %}
      entity_id: sensor.time
1 Like
4

Determining if the current date is even or odd is a calculation that only needs to be performed once per day, just moments after midnight

Basing it on sensor.time means it will be evaluated every clock tick, so it’ll be doing that not once per day but umpteen times a day. Kind of a lavish use of CPU cycles for something that only needs to be done once, at the beginning of the day.

I don’t know what is your use-case for this even/odd sensor but you can have an automation, scheduled to run a few seconds after midnight, perform the calculation can then call a service or set an input_boolean (off=odd, on=even) or whatever.

5

To piggy back off @123, you can incorporate the date sensor (part of the time sensor), and use that instead. Also, you can simplify your template.

# Monitor if date is odd or even
- platform: template
  sensors:
    odd_even:
      friendly_name: "Date Odd or Even?"
      entity_id: sensor.date
      value_template: "{{ 'Odd' if now().day % 2 else 'Even' }}"

or just having a binary_sensor to tell you if it’s an odd day:

binary_sensor:
- platform: template
  sensors:
    is_odd_day:
      friendly_name: Odd Day?
      entity_id: sensor.date
      value_template: "{{ now().day % 2 }}"
1 Like
6

Thanks for all the suggestions. The calculation only needs to be performed once per day so i have set up an automation that simply forces the sensor to update at 1 minute past midnight by calling the homeassistant.update_entity service and passing it the code as follows. Seems to work great :slight_smile:

{
  "entity_id": "sensor.odd_even"
}
7

what I would like to do: a different value every day, but even Wednesdays assign a value, odd ones another value. Can you tell me where is the error on this code?

  • platform: template
    sensors:
    sensor name:
    entity_id: sensor.date
    friendly_name: “mysensor”
    value_template: >-
    {% if now().weekday() == 0 -%}
    cat
    {%- elif now().weekday() == 1 -%}
    dog
    {%- elif ((now().weekday() == 2) and
    {{(as_timestamp(now())|timestamp_custom (’%U’) | int % 2) == 1 }}) -%}
    fish
    {%- elif ((now().weekday() == 2) and
    {{(as_timestamp(now())|timestamp_custom (’%U’) | int % 2) == 0 }}) -%}
    bird
    {%- elif now().weekday() == 3 -%}
    frog
    {%- elif now().weekday() == 4 -%}
    fox
    {%- elif now().weekday() == 5 -%}
    lion
    {%- elif now().weekday() == 6 -%}
    mouse
    {%- endif %}
8

Please format your code so others can easily read it.

To format code, select it then click the </> icon.
Alternately, type three consecutive back-quotes ``` on a separate line before your code then three more on a separate line after your code

9

You have templates in templates (not allowed) and you don’t need to do that crazy conversion to get the even or odd days.

{%- elif now().weekday() == 2 and now().day % 2 -%}
fish
{%- elif now().weekday() == 2 and not now().day % 2 -%}
bird
1 Like
10

sorry but it was my first post. thanks petro, it works perfectly

1 Like