Pseudonymous maker “Aquaticus” has designed a kit to get your energy, water, or other IEC 62056-21-compatible meter talking to Home Assistant or other smart home platforms, dubbed the PiggyMeter — thanks to its snout-like appearance.
“The PiggyMeter can read data from an electric meter or any device with a compatible interface,” Aquaticus explains of his creation, which communicates with the meter over an IEC 62056-21 connection. “It uses widely available components, open source software, and is compatible with the popular home automation software Home Assistant.”
I had a look at my pre-paid meter in South Africa, to check, and interestingly enough, although it does not actually have such an interface, there is part of a circular recess barely visible, and in the centre can clearly be seen the faint outlines of where the two holes would be. It looks like the holes could have been pressed out to accommodate such an interface. In my case, I’m using a Hall Effect sensor clamped around the live wire to read power draw.
So, an alternative is other a Hall Effect sensor which would be fully universal across any meter.