It was originally part of a confessional booth taken to Burning Man in 2015. Since then it has evolved and become part of my smart home stuff.
I was intimidated when I started as it was my first "hardware" project, but the rotary phone part was pretty easy! Just a little switch that turns on and off the number of times of the number dialed basically.
It actually has a (new) microphone wired into the mouthpiece and it uses the receiver original speaker ired to the pi sound output.
(At the time I knew nothing about Linux so I think getting pulseaudio working correctly took as long as everything else!)
Those aren't working currently, but eventually I plan to integrate both the rotary dials and voice recognition and "scenes"
So like, dial "721" for light control. Voice: "And what are we doing with the lights today..." Me: "Make the outside light purple" and it is done.
I have custom voice recongition for things like that working with Mycroft, so it will just be a matter of joining the two projects!
As a bonus, since it was originally designed to work in the desert without a screen, it can do things via a weird analog interface. For example, if I press the hangup button 10 times in a row and then dial a number, I can get a report of how much memory is left on the device, etc.
2) Wired one into a rotary phone to make a weird steampunky smarthouse controller (Dial '0' to turn off all downstairs lights and music, etc)
3) Various LED controls for fun, and Christmas
4) Always experimenting with MycroftAI to stay away from Alexa