He reasoned that he could tap into the low-voltage side of the doorbell transformer and watch for the telltale fluctuations that would indicate the bell was doing its thing. The ESP8266 has an ADC ...

[Open Frime TV] has a video addressing this in a novel way, by creating the windings for a switch-mode power supply transformer using stacked PCB coils instead of wire (Russian language ...

Locate the doorbell transformer, if replacing. The transformer may be in the garage or utility room, near the doorbell chime or in the attic. The post How To Wire a Doorbell Transformer appeared ...