Can you use esphome and nodemcu to monitor doorbell transformer?

I started using esphome for multi sensors and absolutely love it. Is their a component I can use and possibly connect to my doorbell transformer to detect when someone presses the button? Or perhaps some other setup that would utilize the nodemcu? Thanks!

Hi, I do not understand what you mean with doorbell transformer. But you can attach a pin of the nodemcu to the button with a pull down resistor and use a binary sensor.

I was curious, could I use an ac current sensor to detect when the button is pressed, by monitoring the current of the doorbell wires coming out of the doorbell transformer?

The short answer is yes, using the sensor to send to mqtt

What AC detector are you planning to use?

Yes, you can send the current to home assistant via mqtt or the api and make automation using the current level to change the state of other entity

Not sure. One that works with nodemcu and esphome?

I asked because I haven’t found an inexpensive AC current sensor that would respond to the low current of the doorbell circuit; typically 500 mA. I was thinking of a doorbell detector before my wife reminded me that our dog was much louder than the doorbell, and she usually started barking before the guest even reached the doorbell, so that project got shelved.

Your wife barks at the door?

Sorry, I have nothing useful to say.

I’ve considered converting the door bell to send a DC signal to an esp unit. It would then trigger a relay for the doorbell AC circuit. No current sensing needed.

Woof!
I thought of two ways to do this. One would be a small resistor, 1 or 2 Ohms, in series with the doorbell, then build an AC-DC circuit around the resistor. When the bell is rung, you should see a small voltage that the analog input would detect. The other would be a rectifier bridge across the doorbell and a resistor voltage divider to bring the level down to between 3-5 Volts that the ESP could safely detect.