It uses a dedicated single-phase AC voltage sensor module ZMPT101B ... To “see” the output of your ZMPT101B module, just follow the wiring scheme shown above, and upload below code to your Arduino Uno ...

All it uses is a TSL261 Light-to-Voltage sensor connected to an Arduino with an Ethernet shield attached. The sensor is then taped above the meter’s flashing LED, which flickers whenever a pulse ...