Single-phase student energy meter using ATM90E26 metering IC, STM32F103 MCU, OLED display, USB-UART communication, transformer voltage sensing, and SCT013 current sensing. Designed for a 2-layer PCB within 150 mm x 150 mm and a BOM target below 50 EUR.

Industrial Class 0.5 three-phase energy meter with STM32G431 metrology/control, ESP32-WROVER-E Ethernet/WiFi communications, ATM90E36A metering front end, RS485, industrial HV/LV isolation, and 4-layer pre-layout constraints.