This is a niche, but commercial product using ESP32: https://lectronz.com/products/pow-u-han-port-reader-for-m-bus-meters-esp32 https://lectronz.com/products/po

This is a niche, but commercial product using ESP32: https://lectronz.com/products/pow-u-han-port-reader-for-m-bus-meters-esp32 https://lectronz.com/products/pow-u-han-port-reader-for-m-bu... I use it and it's crazy how much it can do with close to no power.