One of the most popular projects we’ve featured here was Dave Hunt’s PiPhone . It’s a working mobile phone built around a Raspberry Pi; it does all the telephony you’d expect, but it’s a smart-ish phone, not a complete smart phone, which made some of you sad. In the year since the PiPhone was first built, Tyler Spadgenske has been beavering away at his own version, which improves on the original.

See the article here:
TyFone – a DIY Smartphone