my idea is to receive a value over MQTT or HTTP request and write this value to a virtual Device or variable.
In case of MQTT there is a tag “message received from topic”, but this tag is only available for comparison/Logic in the AND flow. I see no possibilities to use the value that is in the message Tag to use it in the THEN flow.
I think the main reason will be, that the message is a STRING and it has to be converted to a number before it can be used for a “set value”.
Are there any other possibilities to receive values from outside and use this values in homey flows?