Home made cellphone project.
Above, far left, is one of Adafruit’s capacitive touch displays. Its actually an Arduino shield for the original Arduino Unos. I love these displays because they fit in a small case. I do have to modify it a little though. There is a 6 pin connector that I need to remove. You can see the 6 solder pads where I pulled it off at the bottom of the board in this picture.
The silver thing at its top of the display board is the SD card slot. Basically the phone’s hard drive.
Green board in bottom middle is the Teensy 3.2 that runs the user interface. The rightmost brown board is the FeatherFONA. It has all the different bits of hardware needed to make this a working cellphone. Big round black thing at the top is the speaker. There is actually a tiny microphone hidden under the Teensy processor. The green thing at top with green rectangles is the cellphone antenna.
Sticking the bits together.
Original layout.
I’d realized that the FeatherFONA with its 2k of RAM wasn’t going to run a GUI. In fact, just running the phone chip itself was about all it could do. What I really liked about the FeatherFONA was that it had pretty much all the hardware needed to build a phone. It had the phone chip, the sim card holder, an amplifier for the speaker, a preamp for the microphone. A LiPO battery charging circuit. Not being a hardware guy I was just tickled to have all these bits ready to go.
As for the GUI? I added in my current favorite µprocessor, the Teensy 3.2, to amuse the user and run the show. This is also an Arduino compatible processor so I could use all the same libraries and tools for both.
As for the case, I started with my original calculator case and stretched it some to fit the speaker. Then swapped out the battery charging circuit for the FeatherFONA. Well, that and other tweaks here and there.
A note about wire..
Adafruit sells this 30 AWG silicon wire. BUY IT! I know I’ve gone one about this stuff before. But it is SO NICE to work with! It makes these tiny little projects doable.
Starting assembly of phone #1. Left to right. FeatherFONA, teensy, antenna, Touchscreen.
