Create JAG/TI WIndChill sensor

Mariusthvdb · February 5, 2018, 4:49pm

HI

Using the windspeed and temperature, im trying to create the WindChill formula in a template.

should be this:

Tgevoel(°C) = 13,12 + 0,6215Tlucht + 0.3965(Tlucht - 28,676)*S10m0,16

valid for:

Tlucht = -46 … +10 °C en S10m = 4,8 … 177 km/h (1.34 … 49 m/s)

with my given sensors this should be something like:

- platform: template
    sensors:
      wind_chill:
        friendly_name: "Wind Chill"
        unit_of_measurement: 'C'
        value_template: "{13.12 +{ 0.6215*{{states.sensor.br_temperature.state}}+ {0.3965*{{states.sensor.br_temperature.state}} - 28.676}*{{states.sensor.br_temperature.state}}*0.16}"

There’s plenty of issues here, but the documentation isnt helping me yet. Please have a look with me?

Thanks,
Marius

fabaff · February 5, 2018, 4:55pm

Use the “Templates” in the Developer tools to check if you have a syntax error in your template and if you are able to evaluate it.

Mariusthvdb · February 5, 2018, 4:56pm

yes i am:

no error, but no value either yet…
did a mistake, should have used windgust (maybe speed) but thats a detail:

{13.12 +{ 0.6215*{{states.sensor.br_temperature.state}}+ {0.3965*{{states.sensor.br_temperature.state}} - 28.676}*{{states.sensor.br_windgust.state}}*0.16}

fabaff · February 5, 2018, 5:22pm

Will not work inside a template. You are doing math.

Mariusthvdb · February 5, 2018, 7:22pm

Ok Thanks. But now what?
Python script for something this small?
Or ill have to look for assistance with @olskar who also wrote https://github.com/olskar/home-assistant/blob/2fc65ab1f7c476e9df4530b3bd83718f6710eaf4/homeassistant/components/sensor/mold_indicator.py
Was hoping for some simpler template option tbh.

Cheers,
Marius

fabaff · February 5, 2018, 10:33pm

Replace it with a ( and the closing one ()) inside the template.

Mariusthvdb · February 5, 2018, 10:43pm

im really sorry, but i don’t fully understand what you say i should change:

(13.12 + 0.6215*{{states.sensor.br_temperature.state}} + 
                   0.3965*({{states.sensor.br_temperature.state}}- 28.676)*{{states.sensor.br_wind_gust.state}}*0.16)

or

(13.12 + 0.6215*states.sensor.br_temperature.state + 
                  0.3965*(states.sensor.br_temperature.state-28.676)*states.sensor.br_wind_gust.state*0.16)

both wont work…
must be missing the crucial point here…

Marius

Mariusthvdb · February 6, 2018, 6:24am

this should be the correct math, now how to get it calculated:

(13.12 +( 0.6215*{{states.sensor.br_temperature.state}}))+ (0.3965*({{states.sensor.br_temperature.state}} - 28.676))*({{states.sensor.br_temperature.state}}*0.16)

or even this:

13.12 +0.6215*{{states.sensor.br_temperature.state}}+ 0.3965*({{states.sensor.br_temperature.state}} - 28.676)*{{states.sensor.br_temperature.state}}*0.16

fabaff · February 6, 2018, 3:43pm

Seems to work for me

{% set temperature = 25 %}

The temperature is {{ temperature }}. 
The calculated value is {{ (13.12 + (0.6215 * temperature ) + 
(0.3965 * ( temperature - 28.676 )) * (temperature * 0.16)) | round(2) }}.

Mariusthvdb · February 6, 2018, 6:05pm

yes, works here too.

but when i replace {{temperature}} with {{states.sensor.br_temperature.state}} this is displayed:

Error rendering template: TemplateSyntaxError: expected token ':', got '}'

{{ (13.12 + (0.6215 * {{states.sensor.br_temperature.state}} ) + 
(0.3965 * ({{states.sensor.br_temperature.state}} - 28.676 )) * ({{states.sensor.br_temperature.state}} * 0.16)) | round(2) }}

spot the error…

fabaff · February 6, 2018, 7:37pm

Remove the {{ }} around the variables.

Mariusthvdb · February 6, 2018, 7:47pm

i tried that:

{{ (13.12 + (0.6215 * states.sensor.br_temperature.state ) + 
(0.3965 * (states.sensor.br_temperature.state - 28.676 )) * (states.sensor.br_temperature.state * 0.16)) | round(2) }}

but then nothing at all is displayed in the result window.

fabaff · February 6, 2018, 7:59pm

If the state is missing (wrong name, not set, etc) then the variables are evaluates blank.

Mariusthvdb · February 6, 2018, 8:13pm

sure, but it is there:

strange, the state is correct, the math is correct (using your temperature statement ), and yet there’s no result combining the two.

fabaff · February 6, 2018, 10:26pm

I think that it’s not working because we were missing the conversion 13.12 + (0.6125 * float(states.sensor.br_temperature.state)..... Jinja could be more strict than expected.

Mariusthvdb · February 6, 2018, 10:40pm

BIngo!

Now thesis obviously incorrect (freezing 2 degrees celsius at the moment), but the math is passing, thanks you very very much!

while this has become a template sensor formatting thread, please let me ask you another boggling question:
why does:

- platform: rest
  resource: http://192.168.xxx.xxx/api/dmH4lHTTsBu1gzhEuVkbV52AwSQpojSYxaxM9pQq/sensors/2
  value_template: "{{ as_timestamp(value_json.state.lastupdated) | timestamp_custom ('%H:%M') }}"
  name: 'Update Dimmer switch'

show the time in the desired format:

and

    hue_dimmer_switch_1_updated:
      friendly_name: 'Dimmer switch1 update'
      value_template: "{{states.sensor.hue_dimmer_switch_1.attributes.last_updated | timestamp_custom ('%H:%M')}}"

show (no matter what i change in the timestamp formatting, or even delete it):

the latter 2 are the same sensors with either states.sensor.hue_dimmer_switch_1.attributes.last_updated or states.sensor.hue_dimmer_switch_1.last_updated

the timestamp doesn’t work in these sensors?

Mariusthvdb · February 6, 2018, 10:58pm

btw this is better:

"{{ (13.12 + 0.6215*float(states.sensor.br_temperature.state) + 0.3965*float(states.sensor.br_temperature.state) - 28.676) * float(states.sensor.br_wind_gust.state)*0.16) | round(2) }}"

yields:

which feels more appropriate right now

Thanks again! Also learned that the starting and ending () are necessary for the | round(2) to work correctly. Magic.

Mariusthvdb · February 7, 2018, 7:58am

Have a final solution worked out and also created another formula, the Steadman.

both sensors for you to use and adapt as you need to localize:

- platform: template
  sensors:
    jagti_windchill:
      value_template: "{{ (13.12 + 0.6215*float(states.sensor.br_temperature.state) + 
                        0.3965*(float(states.sensor.br_temperature.state) - 28.676) *
                  (float(states.sensor.br_wind_speed.state)*3.6)*0.16) | round(2) }}"
      unit_of_measurement: "°C"
      friendly_name: Jag/Ti WindChill

# Tchill(°C) = 13,12 + 0,6215*Tair + 0.3965*(Tair - 28,676)*S10m0,16
# S10m = windspeed (km/h) at anemometer_height = 10 m, Tair in °C

    steadman_windchill:
      value_template: "{{ (1.41 - 1.162*float(states.sensor.br_wind_speed.state) + 
                        0.98*float(states.sensor.br_temperature.state) + 
                        0.124*float(states.sensor.br_wind_speed.state)**2 +
                        0.0185*float(states.sensor.br_wind_speed.state)*
                        float(states.sensor.br_temperature.state)) | round(2) }}"
      unit_of_measurement: "°C"
      friendly_name: Steadman WindChill

# Tchill(°C) = 1.41 - 1.162*S + 0.98*Tair+0.0124*S2 + 0.0185*S*Tair
# Tair in °C en S= in m/s.

fabaff · February 12, 2018, 6:14pm

I guess that we should add those sensors to the documentation.

Hjb · February 12, 2018, 8:28pm

For the JAG/TI sensor there is a small typo; iT should be **0.16 (double asterisk).
Anyway thanks for this, very helpfull.