I am struggling with the electronics of this hook up could someone shed some light – I have everything else ready to go except for detecting the current. Even if I have to run another wire to the box and intercept the switch first NP.
I would use a bridge rectifier to get a DC voltage from the incoming 16Vac and then use one of these (you can get them on AliExpress etc as well) step-down regulators to create 5Vdc to run a Wemos D1 mini or similar and code it with ESPhome. Use the current sensor you linked as an input to the Wemos.
I ended up using and esp8266 with a seperate 5v USB. It has VIN and GND which are the 5V out rails that pull directly from usb.
So with no load it was floating around 0.71V to 0.73V. In esphome I offset the value by 0.722, that way I got values around 0 but never under. I plugged in the ACS712 just like in the picture above (except remove multimeter). Then I set up an automation for when the value of the sensor drops below 0 to trigger the camera snapshot and notify my android.I’m guessing the voltage drops and the sensor sees this. I changed the polling to 60ms (to theoretically match 60Hz, and removed the sensor from recorder and history.
All works well!!!
Only thing that doesn’t work is <1ms rings on the bell but most people ring longer than that so I think that creating a problem that isn’t there.
I’d like to see someone press the doorbell for less than 1ms.
I was thinking about this and another way to interface with a higher voltage device is an optocoupler. There are plenty of sites on the net will explain that if you are unfamiliar.