Showing delta value in dashboard

hi there, i’m new with

i record meter readings from water meters in buckets. How can I display the delta value in the dashboard? For example, I want to show how much water a tenant used this month, the month before and the current year.

I am not getting ahead and have not found any information about this anywhere.

thanks for your help!


Currently there is no way to estimate those kind of values automatically, to get it estimated it should be done at the device or by a fucntion in node red.

What would I do? I would store those values as device properties (and to recover the counters if the device resets), and set a routine to store the last month value, and current month/year value, for this the device should know the date, I would try to get it by a NTP client and keep counting time at the uC, from time to time syncronize it again to get rid of any deviation.

Hope this helps.