Raspberry Pi smartphone with 2G support
Tyler Spadgenske’s entry to 2015 Hack-A-Day Prize contest is tyfone, a DIY smartphone with 2G support using the Raspberry Pi, a 3.5in touchscreen display, and an Adafruit Fona module.
The Raspberry Pi handles all the processing, and connects everything together. The TFT talks to the Raspberry Pi over SPI, and the FONA talks to it over UART. Everything is powered with a 1200mah battery connected to the FONA.The FONA has a charging circuit perfect for use with the phone. Since the battery is only 3.7v, a power boost is used to boost the voltage to 5v for the Raspberry Pi and TFT. A metal speaker and microphone is connected to the FONA for audio, along with an antenna. The FONA also has a real time clock built in, so the Raspberry Pi can keep time even when off wifi connection. The Raspberry Pi also has a USB Wifi Adapter connected to it giving it internet access. Right now all that it is used for is to upload camera photos to dropbox, but more features will be implemented in the future. The Raspberry Pi camera module is used for pictures and video.