MQTT sensors missing in Alexa app

I’m have Nabu Casa account for several month now, and decided to use the Alexa integration.
Installed the app, connected to Nabu Casa, and most of my switches, lamps, thermostats etc are shown.
Most of my temperature sensors are shown as well (under ALL DEVICES tab), but one (for me important one) is missing.

It’s the pool temperature sensor. This sensor is a bit special, as it’s an ESP11 that sends temperature every 15min and then goes to deep sleep - in case this matters.

This is the config from sensors.yaml (like many others)

- platform: mqtt
  name: "Poolthermometer Temperatur"
  force_update: true
  state_topic: "Wifi.Poolthermometer/Temp"
  value_template: '{{ value_json | round(2) }}'
  unit_of_measurement: "C"

image

The light in the first row which is a tasmota device is shown fine in Alexa, the temperature is not.

Are MQTT acclaimed sensors a problem? And how can I get the sensor integrated in Alexa?

This seemed to be an easy one. By comparing this sensor to others that were exposed to Alexa, i first thought it was the device_class, so I set it to “temperature”, but that didn’t help.

It was the little ‘°’ symbol that makes HA notices that it’s a temperature.

So this is what the correct configuration has to look like, and now the pool temperature is known by Alexa as well:

- platform: mqtt
  name: "Poolthermometer Temperatur"
  force_update: true
  state_topic: "Wifi.Poolthermometer/Temp"
  value_template: '{{ value_json | round(2) }}'
  unit_of_measurement: "°C"
  device_class: temperature