Telephone

 Goal: using an rotary phone as input and output device

Step 1: Reading rotary numbers

Connecting the phone

Dutch connector: http://www.matilo.eu/technish/oude-telefoon-aansluiten/?lang=en

Connect pin A (red) to +5V

Connect pin B (blue) to input Arduino

Connect gnd (yellow) to GND => not really needed

Tested: 12...15V, 50Hz is minimal needed to rinkle bell (only tested when B is conneced to GND)