David Hunt’s DIY PiPhone. (via DavidHunt)

There are literally thousands of Raspberry Pi projects that have been posted on the internet since the device was introduced to the market as a learning tool way back in 2012 and while some border on the mundane (using it simply as a PC) others are truly unique. Case-in-point- programmer/photographer David Hunts do-it-yourself Pi-based PiPhone project, which turns the popular single-board computer into a cellphone. The phone, as it is at this point, doesn’t rival current smartphones or even cellphones for that matter, however it IS a cellphone essentially and does function as any cellphone should. David created his PiPhone using off-the-shelf parts and makes use of the Raspberry Pi as its foundation, a hub of sorts that binds everything together. Connected to the Pi is a SIM900 GSM/GPRS communications module, which is attached VIA UART, allowing the device to send AT commands in order to make phone calls, send text messages, hang-up, etc. The module features a SIM slot that allowed David to insert his prepaid SIM card to initialize his device in order to make calls over his preferred network. The phone is outfitted with a rechargeable LiPo battery (complete with on/off switch) with a DC-DC converter, which transitions the native 3.7 volts to a beefier 5 volts needed to power the phone. An Adafruit TFT touchscreen display (320 X 240) was used as the phone’s input panel and is programmed to display simple numbers and a phone icon to answer calls as well as hanging up. That’s it. That’s all there is to the PiPhone, which is all that it was meant to be as David created it as a cheap, proof-of-concept device. The cost breakdown is as follows:

Raspberry Pi (model B)- $40

Adafruit TFT touchscreen display- $35

2500mAh LiPo battery- $15

SIM900 GSM/GPRS module- $48

DC-DC converter (bought on EBay)- $10

Cables and zip-ties to hold it together- $10

Total for the PiPhone project- $158

As you can see, the project was very inexpensive to design and David will upload the software he created to GitHub for those interested in reproducing his creation. However be forewarned as there are some drawbacks to his design. Users will need a headphone/mic adapter to actually make calls, as there are no speakers or microphone present on the device. There is also no word on how long the battery will last while making calls or on standby for that matter, however this is speculation that it’s only a couple of hours. As a testament to the public mind, David took his PiPhone to his local FabLab to showcase his creation and afterwards a member of the audience had asked if ‘they had to pay for credit’ in order to use the phone. Since it uses a prepaid SIM card from a local provider, the answer is obviously yes, however it never hurts to ask.

I like the zip-ties holding all together!


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