Telling if an input of 0 is being sent


I have several inputs from mqtt sensors that feed gauges, in between I have a timeout node that sends 0 to the gauge if there is no input within a 20 minute period so that I can see that something is wrong, I need a node that can tell if a zero is sent so that I can send an email to alert me of the problem, I have looked through the flows library but if you don't know what your looking for it can be a minefield, if anyone could suggest something I would be grateful.


Check the trigger node

what about the switch node? Just test for a 0

If I'm understanding you, can't you do that with the already-included switch node?

Thanks guys the switch node works fine == 0