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 ...

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 ...

The other model is technically identical, except for it being powered from your existing doorbell wiring, or from mains power via the included DIN rail transformer. This doorbell records video at ...