Then he decided to go cellular. He had already hooked up an old ITT 500 series dial phone to an Adafruit Fona ceullar board. He even has Teensy software to decode the dial, drive the dial tone ...

If you have a Raspberry Pi and an Adafruit TFT, you’re halfway to making your own version of [Dave]’s PiPhone. This tasty proof-of-concept cellular sandwich is made by adding a Sim900 GSM ...