Say hello to the open source cellphone

Would you pay $400 for a handful of microchips and, armed with only a circuit diagram, build your own cellphone? With elegant, powerful phones already on sale for a fraction of the price it's not something that will appeal to many. Yet despite the cost and inconvenience, a growing group of techies are attempting to build the first practical home-made cellphones. They hope to spark greater innovation in cellphone design and, more crucially, in the software that makes the phones work. Their aim is to develop a critical mass of free software that will lead to a flowering of new cellphone applications. Some foresee phones acting as affordable hand-held computers running novel applications tailored to the needs of the developing world. The movement is riding on the back of a burgeoning market in wireless devices for machine-to-machine communication. These devices are, in effect, stripped-down cellphones, and a typical application combines them with position sensing systems in trucks, which can then be tracked while on the move. To turn one of these basic cellphone modules into a fully functional phone suitable for chatting to friends, you add a microprocessor, typically running the open-source Linux operating system, along with a speaker and microphone, screen, battery and keypad.