Cannot select unit conversion in HomeAssistant

[Lackmake]

I have a few smartplugs where i can manually select how HA should display the power values, like this:

For the AI-on-the-edge entities however i cannot. The option is completely missing:

What i found is that the rate-sensor is missing the "device_class" attribute. That would have to be added here for both "rates", i think "power" would be correct as thats what my smartplugs report:

AI-on-the-edge-device/code/components/jomjol_mqtt/server_mqtt.cpp

Lines 187 to 198 in 67c3020

	// Group | Field | User Friendly Name | Icon | Unit | Device Class | State Class | Entity Category
	allSendsSuccessed |= sendHomeAssistantDiscoveryTopic(group, "value", "Value", "gauge", valueUnit, meterType, "total_increasing", "", qos);
	allSendsSuccessed |= sendHomeAssistantDiscoveryTopic(group, "raw", "Raw Value", "raw", "", "", "", "diagnostic", qos);
	allSendsSuccessed |= sendHomeAssistantDiscoveryTopic(group, "error", "Error", "alert-circle-outline", "", "", "", "diagnostic", qos);
	/* Not announcing "rate" as it is better to use rate_per_time_unit resp. rate_per_digitalization_round */
	// allSendsSuccessed |= sendHomeAssistantDiscoveryTopic(group, "rate", "Rate (Unit/Minute)", "swap-vertical", "", "", "", ""); // Legacy, always Unit per Minute
	allSendsSuccessed |= sendHomeAssistantDiscoveryTopic(group, "rate_per_time_unit", "Rate (" + rateUnit + ")", "swap-vertical", rateUnit, "", "measurement", "", qos);
	allSendsSuccessed |= sendHomeAssistantDiscoveryTopic(group, "rate_per_digitalization_round", "Change since last digitalization round", "arrow-expand-vertical", valueUnit, "", "measurement", "", qos); // correctly the Unit is Unit/Interval!
	allSendsSuccessed |= sendHomeAssistantDiscoveryTopic(group, "timestamp", "Timestamp", "clock-time-eight-outline", "", "timestamp", "", "diagnostic", qos);
	allSendsSuccessed |= sendHomeAssistantDiscoveryTopic(group, "json", "JSON", "code-json", "", "", "", "diagnostic", qos);
	allSendsSuccessed |= sendHomeAssistantDiscoveryTopic(group, "problem", "Problem", "alert-outline", "", "problem", "", "", qos); // Special binary sensor which is based on error topic
	}

But i am not 100% sure if that is the only reason why home assistant doesnt let me choose the unit....i also found this old thread about the "native_unit_of_measurement": https://community.home-assistant.io/t/unit-of-measurement-2022-4/409860/16

[caco3]

The tricky part is that you also can use it for something else than energy (eg. water). Because of this, you have to select the meter type in the MQTT config:

It then should show up correctly in HA.

But I have to note that I only tested it with a water and a gas meter. I don't measure the electricy with AIOTED.

[Lackmake]

I set the correct metertype in AIOTED and the values do show up with the correct unit in HA, but the HA-feature to convert it to a different unit on the fly isnt available.
But youre correct, i didnt think of other than energy-usecases. In that case the device_class would have to be resolved with a variable like its done for the device_class of "value" in line 188

Edit: For both gas and water the device_class for the rates would be "volume_flow_rate" according to: https://developers.home-assistant.io/docs/core/entity/sensor/#available-device-classes

[caco3]

We would need to see if we can extend the existing implementation without breaking any of the existing functionality.

Starting point:

AI-on-the-edge-device/code/components/jomjol_flowcontroll/ClassFlowMQTT.cpp

Line 145 in 67c3020

/* Use meter type for the device class

Your link interestingly states some different units, eg. L/min although until now we only provide L/h and nobody missed it....

[caco3]

I created an issue for it: #3333
Please continue the discussions there.