The S0-interface in a kWh-meter is an Open Collector type transistor-interface. You need a pull-up resistor to VCC to get a signal which can be counted by the ESP8266, but that introduces 2 points of attention: 1) at the side of the kWh-meter sometimes for reliable operation of the S0-interface a vo...

@Dylantje The ML8511 and GUVA-S12SD devices from Adafruit (or direct from China) generate a DC-Voltage which can be interfaced to the ADC-interface of the ESP8266: support by ESPEasy is simply as an analogue signal at the ADC-port. If you want UV-measurement digitally by means of the I2C-interface, ...

Another Dutchman. Got at ESP8266s while experimenting with Domoticz to expand the functionality for my Solar PV-System and for my Meteo-System. Objective: add extra sensors, applying LAN for communication. [LAN preferably by cable because of reliability, WiFi second choice, but ;-) easier to fit in ...