I have connected analogRead(An) to a speaker that is driven by low voltage 0.5 - 1.5, that speaker is just a "standard" home interphone system which "rings" when you press the interphone bell. I am aware that I cannot continously read that voltage because it is AC. I cannot use bridge rectifier be…

Reading "ac voltage pressence" using software only.

Paul_KD7HB May 27, 2018, 1:56pm 2

Easy! Make the bridge rectifier out of individual small-signal diodes.

Paul