I have a system with what is supposed to be a +12V supply, push button and then a bell (Bell.png I think, I cannot see the back of the PCB on which the transformer, bell, switch are mounted). When I measure the potential difference I actually get ~+9.9V.
What I want to do is notify a MCU (probably a nano to start with, later being replaced with a ATTINY85@5V with power regulator) when the button is pressed. I think the second image (MCU.png) should do this, but I just want to check as it’s been a long time since I’ve done anything like this.
Thoughts, comments and improvements are very much welcome.