This is what happens when you use the Raspberry Pi single-board computer to build a phone
Mr. Hunt's homemade phone is powered by the $40 Raspberry Pi Model B computer, which is identical to the one that graces the insides of the PiPad. The PiPhone also houses a SIM900 GSM/GPRS module, which comes with the sole purpose of connecting the device to the carrier's network. The display of the device is a resistive PiTFT touchscreen, which sports a resolution of 240 x 320 pixels and comes with a 16-bit color depth.
The creator of the PiPhone uses a 2500mAh Li-poly battery to power his homemade gadget. Although this might seem like an overkill for a gizmo that only comes with the most basic functions, Mr. Hunt suspects that it won't provide more than several hours of life for the PiPhone due to the lack of software optimizations. Speaking of software, the PiPhone runs a custom script, which is written in Python by Mr. Hunt himself.
The whole shebang cost Mr. Hunt some $158 – the GSM module appears to be the most expensive - $48, while the display and the chipset hurt his wallet less - $35 and $40, respectively. Although it looks like it was assembled with Lego blocks by a kid, the PiPhone is a rather curious project, which might teach us to appreciate affordable devices, such as the $62 Nokia Asha 230, a little bit more.
source: David Hunt Photography via Pocket-lint