Electronic

Schematic

The watchdog IC U2 is not needed and should be removed from the PCB in the future. Same for snubber circuits C1 and R6 + C2 and R10.

PCB

About power supply

The 230 VAC power supply Kamstrup supply does not give enough current for wireless peak usage, so we built our own with a 2A switched mode power supply from AliExpress supplier Kuuco's store customized to 3.6 V to keep the Kamstrup meter happy.

https://www.aliexpress.com/item/3-5W-Power-Adapter-AC-110V-220V-85-265V-to-DC-3-3V-1A-Switch-Power/1861156180.html?spm=a2g0s.9042311.0.0.DFaxcV