Hi HA Crew,
I made this and got it working well! 3D printed funnel, cup and holder, integrated a Wifi door contact (I used TPLink Tapo). The rocking of the cup, counts the “door open and close”, and you can do the maths to calculate amount of rainfall in mm.
All credit to smartsolutions4home.com for the design and inspiration!
Sounds great. Details would be welcome 
See here for plenty of tips and tricks
Actual article pertaining to OP project:
So far so good!
I have found that the daily graphs are not correct - and I am stumped on the maths… “today” will show yesterday’s value. “Yesterday” seems to be a sum of the last 48 hours… day before that seems to be last 36 hours…
