Trigger rule on empty MQTT message?
Is anyone aware of any way at all to trigger a rule to execute if openHAB receives a blank message via MQTT?
At the moment the below code works but only if the message contained a value, i need it to trigger if the message is blank.
rule "solve" when Item monitor1 received update then V_VAR1send.postUpdate(V_VAR1.state) end
I have a open question on the openHAB forum but wondered if anyone around here has done something similar?