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 ...

Step 2: Find and Inspect Your Doorbell Transformer Use a multimeter set to "AC volts" (not "DC volts") and connect it to the ...

A wired doorbell system has three components: a low-voltage (15- to 20-volt) transformer, a chime and a doorbell button. They are connected by 18- or 20-gauge low-voltage wires. Although it's at ...