Are the 2 lines coming out of the upper left corner energized at all time? 5VAC? 240VAC? Is it stable?
I mean, if the L and N screws are at 5V and only going to 240V when someone presses the doorbell… is the other blue & black pair behaving the same??
I am asking because if you want to do Shelly at all, you will need a way to power the Shelly (or anything wifi or ESP based) at all times. And that was exactly the reason why the very 1st post of this thread is talking about a 12VDC power source.
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Otherwise, you will want to look into other devices that are battery powered. 2 ideas:
- There are people repurposing a window/door contact sensor. With clever placements, you do not need the megnet half of the door sensor, and supposed the magnet field changes from the ding-dong strike plate mechanism would be enough to trigger the window/door sensor. example 1, or 2, or 3, or 4
- There is also a thing that is called “Sage Doorbell Sensor”, that was zigbee and was discontinued maybe a decade ago… but still can be found on eBay from time to time. You will need to double check whether that would work with 240VAC wiring, though because that device was designed for the US market I believe. Here is a better read.