Statistics Attributes - Change Rate is constantly 0

@AutoT wrote:

I’m trying to control my dehumidifer by using a Shelly H&T.

In my opinion, using the actual humidity reading isn’t the best approach, instead I should be using rate of change - as that reaches zero, then the room is “dry enough”.

I am reading the Shelly data via MQTT:

  - platform: mqtt
    name: "Shelly HT 1 Humidity"
    state_topic: "shellies/shellyht-F2BA00/sensor/humidity"
    unit_of_measurement: '%'

and then using the Statistics Sensor to get HA to generate stats:

  - platform: statistics
    entity_id: sensor.shelly_ht_1_humidity

As the value of humidity is rising and falling (and fairly static), then I would expect the “Change Rate” attribute to vary, but it’s a constant zero:

image352×635 11 KB

I put the attributes through a template sensor to trend them:

      humiditychange1:
        friendly_name: "Humidity 1 Change"
        unit_of_measurement: '%'
        value_template: "{{ state_attr('sensor.stats_2', 'change') }}"      
      humidityroc1:
        friendly_name: "Humidity 1 Rate of Change"
        unit_of_measurement: '%'
        value_template: "{{ state_attr('sensor.stats_2', 'change_rate') }}"      
      humidityavgchange1:
        friendly_name: "Humidity 1 Average Change"
        unit_of_measurement: '%'
        value_template: "{{ state_attr('sensor.stats_2', 'average_change') }}"

The red line (rate of change) is a flat line at zero.

Is this a bug, or have I misconfigured something?

Thanks for any insight

Posts: 4

Participants: 3

Read full topic