Mqtt trigger.payload

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1

Can anyone help with this syntax?

What is wrong with this line?

brightness_pct: “{% if trigger.payload > 100 %} 100 {% else %} trigger.payload {% endif %}”

I have also tried

brightness_pct: “{% if trigger.payload > 100 %} 100 {% else %} {{trigger.payload}} {% endif %}”

There is no error on a configuration test, but neither example will set the appropriate brightness. I try to use the template work area to test, but trigger.payload is not recognized and adding variables doesnt prove anything because the test area can set an actual brightness.

Thanks

2

The received payload is (probably) a string so it must first be converted to a numeric value (integer or float) before performing a numeric comparison.

brightness_pct: "{% if trigger.payload | int > 100 %} 100 {% else %} trigger.payload {% endif %}"

You can use inline if-else to create a more compact version of the template:

brightness_pct: "{{ 100 if trigger.payload | int > 100 else trigger.payload }}"
3

That was exactly it! Thank you very much!

Just curious, when do you have to use ‘{{’ or ‘{’?

4

{{ }} is for output
{% %} is for everything else: setting variables, logic, etc.

Anything not in either is literal.

2 Likes
5

It’s all described in the first section of the documentation for the Jinja template engine: Synopsis

From the documentation:

There are a few kinds of delimiters. The default Jinja delimiters are configured as follows:

6

Thank you! I appreciate everyone’s time very much.

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7

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8

what if the payload is numeric value already?
I want to set fan based on the temperature from mqtt sensor. If it is below 16.2 it should trigger: Now I have the conditions this way: {{ trigger.payload | int < 16.2 }} but I feel that the int is not needed when it is already numeric value.

EDIT: because now it triggers even when the temp is 16.6 so it shouldn’t.