doorbell

[ascot]

attached is a photo of a doorbell receiver is it possible to attach wires to power it from power supply it's normally powered from the mains and if so were
and also could i be able to attach  esp32 module to it

[eblc1388]

First you would need to measure the DC voltage across capacitor C11(markings 470,10V,VT) near resistor R4, with mains supply ON(so be careful !!!). The whole circuit board might be HOT(Live).

I would guess it would be either around 3.3V or 5V. You can then removes the board from mains connection and connect the external dc supply with approximate same voltage across this capacitor to power up the rest of the circuit. Measure the idle current, and you may need to cut off some circuit tracks if the idle current is too high. Let's do it a step at a time.

[ascot]

i already cut the mains out dc i,m fine with, ac tend to err on caution ,the bell should ring once enough dc current is reached i,m assuming .
just the tracks having trouble reading ie which one is  + which is -

[ascot]

you were right works from 3 and 5 volts trial and error with probes thanks