Here are 2 github repositories used by this project:

https://github.com/pifactory/watermeter

https://github.com/pifactory/kicad-goodies

So far only sensor itself is published, Zigbee microcontroller will be added soon, including firmware and files needed by zigbee2mqtt.

I've got feedback from PCB shop about shorts in the inductor loops. Their answer was that I need to increase the track width and clearance to 125 μm (about 5 mil). This is no surprise, but now I have confirmation from the first hand.

Another problem is that battery of my prototype is down to 92.5%. I will increase counter buffer time to 5min and see if it helps.

For the rest prototype works as expected: counting used water and updating data in Home Assistant. I've created also flows in NodeRed to produce more meaningful "water consumed today" sensor. It is easier to track. Will write about it later