Salah wrote: ↑Mon Oct 22, 2018 8:20 am
I think my intercom is lightly different from the one on the diagram.
Mine has a handset with a separate microhpone and speaker. The speaker I want to wire to the pi only buzz to alert me someone wants to come in, there is no audio voice out of it.
The thin wires white/blue/red goes to the handset. I wired the blue and red ones (ground and handset speaker I guess) to a 3.5mm jack which I plugged to a usb sound stick on the raspberry pi and I managed to get the voice audio on the Pi.
Ah, now I see I am making simple things too complicated.
Let me see, if Rpi's audio input jack can get the signal from the 3.5mm plug connected to the intercom loudspeaker, then you can just write a simple program, say, in python, with the help of so many python audio libraries out there, to do what you want. In other words, there is no extra hardware required for your project.
By the way, the very ancient intercom in my home is similar to yours, except there is no electronic component inside, only wires and switches!
Good luck to your project.