Real time energy consumption tracking

Realizing the meter provided by my power company was equipped with a HAN/P1 port, providing real time data on my consumption, I just had to try and hook it up to Home Assistant.
I know you can buy hardware for this, but it’s not as fun. :)

My electricity meter is from Sagem and provides current consumption data via its HAN port every ten seconds. It uses simple serial communication in a specified format (at least in Sweden).

First prototype using a MKR 1010 WiFi hooked up to a bread board that also connects to the RJ12 on my electricity meter.
The MKR parses the serial data and forwards to Home Assistant using MQTT.

Bread board prototype

Next, create a tiny PCB to get rid of the bread board.

Traces, drill, cut out, and mount circuitry and RJ12 connector.

The PCB mounts like a mini shield on the MKR. If I get around to it I will make cheaper ESP8266-01 version of this, with a nice casing.

(If you want some more details on the simple circuitry, Åke Hedman made a nice write up here.)