i am thinking about this switch, but am unsure if the relay will reset after a trigger state
https://czh-labs.com/products/panel...-signal-control-latching-spdt-relay-module12v

 

Nothing in the pictures gives us any clue. I can guess that the 8 legged IC is a 555 timer, but it may not be that. No telling at all.

 

Description of device says chip is a pic12F675.

 

Not much luck with chime audio, I don't believe V out result, but is chime switch available & what are V measurements referenced to power supply common, - , of switch? How about a 15 sec. timer triggered by chime SW
which drives a transistor SW across MP3 SW?

 

Not much luck with chime audio, I don't believe V out result, but is chime switch available & what are V measurements referenced to power supply common, - , of switch? How about a 15 sec. timer triggered by chime SW
which drives a transistor SW across MP3 SW?

Go back and take a look at post#19 and what the TS tells us there.