This tasty proof-of-concept cellular sandwich is made by adding a Sim900 GSM/GPRS module, which communicates via UART, to the Pi/TFT hardware while using a piece of foam core board in the middle ...

Cellular shields for the Arduino have been around for ages, but this is the first one we’ve seen that turns your Arduino into a proper cell phone. The shield is based around the SIM900 GSM/GP… ...