The Raspberry Pi is a mini computer, just like most smartphones, so it stands to reason that you can create what amounts to a home-brew cellphone out of a few store-bought electronics parts. That’s just what David Hunt did. By connecting a RaspPi to a GSM module, a small TFT screen, and a battery, he’s essentially created a the DIY-est of DIY cellphones.

The total cost for the project was $158 and that included $48 for the GSM module and $40 each for the Pi and a screen. He wrote his own phone interface and all the phone can do is make and receive calls, which is probably some privacy-lovers’ dream come true.

What’s most fascinating about the project is that it requires no soldering or any particularly strenuous electronics knowledge. Because it is made of off-the-shelf components, you could fit one of these together in less than an hour. However, because it could (and does) overheat, Hunt doesn’t recommend stuffing this hunk of electronics into an enclosure, which could put a damper on your rainy day phone calls.

The most ingenious part of the package is the GSM module which is essentially a tiny modem. Writes Hunt:

Once we turn the unit over, we can see the main communications module, which is a Sim900 GSM/GPRS module. This allow us to send standard AT commands to it to make calls, hang up, send texts, data etc. Overall a very clever module. Towards the bottom of the white PCB, you can see the SIM Card, which allows the module to associate with my local GSM network, and it’s using a regular prepaid SIM card, bought in my local phone store for €10.

The fact that this phone would have been impossible to build even a few years ago is staggering to me: we are in an era where almost all electronics can be considered potential DIY projects. Let me know if you try to build one of these in the U.S. because I’d love to see it.

via RaspberryPi.org