(late post, sorry!)
My project is a pair of sound sculptures created with old telephones, which were hacked to become audio recording / playback devices. The first telephone is used purely for audio playback, where dialing phone numbers accesses certain recordings stored in an SD card. The second telephone serves as both an audio recording and playback device.
I don’t have video documentation of the progress, so here’s a pretty photo instead:
For the first phone: I was able to hack into the phone speaker and have it play back recordings by dialing telephone numbers. I also got the Arduino to detect whether the handset is on or off the hook–so people can hang up the phone and the playback will stop.
For the second phone: I managed to get the recording to work with the internal microphone. All I have to do now is fiddle with the speakers + handset and I’m good to go! The code is already completed. Not sure if I’ll add a feature for the rotary dial–maybe if I have time.