[BUG] utility_meter shows to much decimals

[vistalba]

The problem

Utility_meter does show too much decimals (5 in my case). This wasn't the case before.
The input sensor the utility_mater's are based on does have onle 1 decimal as the smalles amount of rain it can detect is 0.3mm.

This doesn't make sense and it wasn't the case as I configured lovelace some weeks ago. The issue began this week.

utility_meter is based on this sensor:

Environment

• Home Assistant Core release with the issue: 0.115.6
• Last working Home Assistant Core release (if known): -
• Operating environment (OS/Container/Supervised/Core): OS
• Integration causing this issue: utility_meter
• Link to integration documentation on our website: https://www.home-assistant.io/integrations/utility_meter/

Problem-relevant configuration.yaml

# utility_meter.yaml
  hourly_regen_garten:
    source: sensor.garten_regenmenge
    cycle: hourly
  daily_regen_garten:
    source: sensor.garten_regenmenge
    cycle: daily
  weekly_regen_garten:
    source: sensor.garten_regenmenge
    cycle: weekly
  monthly_regen_garten:
    source: sensor.garten_regenmenge
    cycle: monthly
  quarterly_regen_garten:
    source: sensor.garten_regenmenge
    cycle: quarterly
  yearly_regen_garten:
    source: sensor.garten_regenmenge
    cycle: yearly

### sensor.yaml
  - platform: mqtt
    state_topic: "rtl_433/5/rain_mm"
    name: "Garten Regenmenge"
    unit_of_measurement: "mm"
    expire_after: 600

### lovelace config
type: entities
entities:
  - entity: sensor.hourly_regen_garten
    name: letzte Stunde
  - entity: sensor.daily_regen_garten
    name: Heute
  - entity: sensor.weekly_regen_garten
    name: diese Woche
  - entity: sensor.monthly_regen_garten
    name: laufender Monat
  - entity: sensor.quarterly_regen_garten
    name: laufendes Quartal
  - entity: sensor.yearly_regen_garten
    name: laufendes Jahr
title: Niederschlagsmengen
state_color: false

Traceback/Error logs

I don't know if this error has to do with this as I use utility_meter for other measurements/sensors too (e.g. power meters).

Logger: homeassistant.components.utility_meter.sensor
Source: components/utility_meter/sensor.py:165
Integration: Utility Meter (documentation, issues)
First occurred: 19:53:27 (12 occurrences)
Last logged: 19:53:32

Invalid state ( > ): [<class 'decimal.ConversionSyntax'>]
Invalid state ( > 13.1): [<class 'decimal.ConversionSyntax'>]

Additional information

[probot-home-assistant]

Hey there @dgomes, mind taking a look at this issue as its been labeled with an integration (utility_meter) you are listed as a codeowner for? Thanks!
_{^{(message by CodeOwnersMention)}}

[dgomes]

Well that error is not normal (Invalid state) and it is caused by the source sensor (sensor.garten_regenmenge) that has an empty string in the topic, your should fix that in the sensor.

About the decimals, python is very tricky about this... you probably received a value in that mqtt topic with a very high precision (or simply an error that was poorly interpreted by python when converting to a decimal), the system will propagate that precision indefinitely...

[vistalba]

The source sensor only can increase by 0.3.

So possible values are always like:

0.0, 0.3, 0.6, 0.9, 1.2, 1.5, 1.8, 2.1, ... and so on.
There is never more than 1 decimal in the source sensor. Otherwise I would just use the round(1) function as value_template on the source sensor.

[dgomes]

I understand your viewpoint, and you expect that to happen. But the errors:

Invalid state ( > ): [<class 'decimal.ConversionSyntax'>]
Invalid state ( > 13.1): [<class 'decimal.ConversionSyntax'>]

tell me otherwise... even if sporadically, there is something strange with your sensor.

From the MQTT topic "rtl_433" I take it you are receiving this from a weather station over a 433Mhz radio link. These links are prone to errors, usually besides the weather readings there is usually also a checksum field that can be used to validate that the received information is correct (well at least with my Chinese no brand weather station :) )

[vistalba]

@dgomes

Yes, I use rtl_433 with a rtl-sdr dongle to receive weather station (rtl433 type -R 32).
There is a CRC value looks like this: mic = CRC
I don't know how it will look like if CRC fails. Until know I thought that rtl_433 will already sort out stuff that didn't pass CRC check. Is that not the case?

Could you show me your mqtt sensor conf as an example?

Also I think about make utility_meter more robust. Why this happens at all? I think utility_meter shouldn't do anything if the source sensor is reporting wrong/strange values or is unknown/unavailable?

In addition i tried now the following:

  - platform: mqtt
    state_topic: "rtl_433/5/rain_mm"
    name: "Garten Regenmenge"
    unit_of_measurement: "mm"
    expire_after: 600
    value_template: "{{ value | float }}"

I think with this value_template the sensor shouldn't report anything if there is no valid digit in the value received from rtl_433.
Unfortunatly this doens't help at all. May I should change to value_template: "{{ value | float | round(1) }}" to also make sure input is always with max 1 decimal?

Edit:
This is how it looks in mqtt explorer:

As you can see there is only the value mic = CRC so I think this value means that the received stuff passes the CRC check of rtl_433. Is this correct?

[dgomes]

I'm not so sure about rtl-433, I use a diy decoder based on an Arduino (https://github.com/dgomes/homeGW) in my code I do handle the CRC before publishing into the MQTT broker. So my configuration is very similar to yours.

I also have a issues with values that are properly transmitted but make no sense! for that I use the filter integration https://www.home-assistant.io/integrations/filter/

Here's my configuration to filter bad values from my weather station:

- platform: filter
  name: "Temperatura Exterior"
  entity_id: sensor.temp_out
  filters:
    - filter: outlier
      window_size: 4
      radius: 5

- platform: filter
  name: "Humidade Exterior"
  entity_id: sensor.humidity_out
  filters:
    - filter: outlier
      window_size: 4
      radius: 20

Your template will fix some errors, but not those outliers that happen not too often.

[vistalba]

I investigated this issue again and added a history to the source sensor sensor.garten_regenmenge and I can see that sometimes HA really receives results with much decimals. Really no clue why this happens.

So I think value_template: "{{ value | float | round(1) }}" on mqtt sensor should solve this and I will try this now. Unfortunatly I've to wait for some rain ;)

I also now monitor the mqtt broker to see which values he is receiving.

Edit:
Now it happens... and I can see that rtl_433 does really report 99.60001 to mqtt broker.

So I will close this issue here, as it isn't a issue in utility_meter or homeassistant at all.
Thanks for support! :D