The WH40 and GW2000 should work OK. The batteries should last well over a year, probably 2 or more. I have the weather station with the solar panel and the batteries are still OK after 3 years.
The operation is the same as the POPP unit where the see-saw rocks back and forth as one side fills up followed by the other. Once the bucket is full the see-saw tips and empties while the other side starts to fill. This does mean they need to be mounted level for the action to work correctly.
The update rate from the sensor is around 15 to 30 seconds and provides the following (except Ultraviolet):
All of which are available in the flows.
Once you have the GW2000, you can expand the system to include moisture sensors. I have these in various places in the garden so I know if it is OK to skip irrigation based on the soil moisture content.
Note: the rain sensor doesn’t need to be mounted up high, like a wind sensor does, as it will catch rain in any space that is not covered.
