Rephone makes modular open source hardware cellphone components — GSM cores, touchscreens, speakers, GPS, miscellaneous sensors, and antennas — that you can mix and match to build cellular capability into everyday gadgets; one project builds a complete cellular phone into a watch-strap for a Pebble smartwatch.
Rephone sells the components, but they're all also open source hardware, with full schematics and sourcecode. The site includes several starter projects. A full kit is $49, while stripped down ones go for $45 or less.
Features
*
World’s first open source and modular phone*
Support Lua, Javascript, Arduino IDE and Eclipse IDE*
Various rich-featured add-on modules for function extension*
DIY Phone*
Last for about 25 hours @ standby (RePhone Kit Create)
(via O'Reilly Radar)