We've seen a ton of great projects from Raspberry Pi owners in the two years since the mini computer has been available, but this one might be our favorite so far. Irish engineer and photographer David Hunt made the official Raspberry Pi blog this past weekend with a build he calls the PiPhone, a smartphone built on Raspberry Pi.
The PiPhone uses an Adafruit TFT touchscreen interface and a Sim900 GSM/GPRS module connected to the board via UART. This enables the PiPhone to function as a phone and actually place calls. Though the device also employs a LiPo battery pack that allows for mobility, Hunt says it's more a proof of concept than anything else. Especially since the PiPhone tends to get a bit warm (there's not a lot of airflow), so putting it in a case to use as an actual phone might be ill-advised.
David reports that the total bill for parts for the PiPhone was $158. It's not extraordinarily cheap, but the fact that this was built entirely from off-the-shelf parts and requires no soldering means it can be done by absolutely anyone. Given Raspberry Pi was originally supposed to be a tool used by children in a classroom setting, projects like this really speak to the Raspberry Pi Foundation's mission of enabling people of all ages to explore computing and learn how to program.