What will you propose to inform user if the message with known topic won't show for some time?
rpi-ds18b20 node to periodically read all my DS' sensors. The network is quite big (I know, 1w was not designed for that) so I've decreased a bit pull-up resistor and generally all is working fine. However, I would like to be informed (and display it on my floorplan) that data from particular DS is missing for some time (I'm reading every minute, so I would guess 3 minutes for 3 readings sounds reasonable to dismiss one-time glitches).
My flow is currently similar to:
inject [every 1'] ->
function: map ID to meaningful topic ->
mqtt and then
join [key/value to store all data] ->
ui_template. The problem with such scenario is that
join node (as described in my previous thread) is updating only new data, so when one of my DS will die or RPi won't be able to read it, it will be lost - the last valid value will be displayed forever.
I was thinking of using
trigger node but that node is not aware of missing data, so that's wrong direction.
This sounds like it should be a popular issue but I wasn't able to track similar problem.