Rtl_433 sensordata with mqtt

with rtl_433 i get this data:
pi2 = {“time” : “2024-07-02 11:15:01”, “model” : “Oregon-THN132N”, “id” : 83, “channel” : 1, “battery_ok” : 1, “temperature_C” : 22.400}
how can i get this mqtt/json data in homeassistant?
- name: Temperatuur-433
state_topic: rtl_433/pi2
unique_id: temperature_C
value_template: “{{ value_json.temperature_C | float }}”
unit_of_measurement: " °C"
device_class: temperature

My data example is not working

Maybe check this:

I read and tried your advice several tims, but there is somethings that i do WRONG.
no , it is not working.

here is an example of an mqtt.yaml entry I have for data pulled from rtl_433 (in this case the temp of a freezer with an rtl_433 sensor inside). I personally find entering them manually in my mqtt is easier, the mqtt auto discovery will pull in a bunch of unwanted entities.

-name: "Garage Freezer Temperature"
  state_topic: "rtl_433/433/devices/Acurite-Tower/A/7172/temperature_C"
  unique_id: "garage_freezer_temperature"
  device_class: "temperature"
  unit_of_measurement: "°C"
  value_template: "{{ value | float }}"
  qos: 0

tht suggestion is ok but how do you get this data tio a dashboard.
Is there not a connection with configuration.yaml needed?

in the configuration.yaml file have the following

mqtt: !include mqtt.yaml

then put the lines I outlined above (adjusted for your scenario) in the mqtt.yaml file.

then after your reboot you will have an entity by the name assigned in the mqtt.yaml file.

thanks,i will try