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Designing my own Phone

Former Member

Hey everybody. I would like to design my own mobile phone. I'm engenieering student and I don't know too much about this world, so I'm asking for the place or the material where I should start looking for information. What I want to do is a kind of old mobile phone, I mean, small and thin like an iPhone 4 or 5 but without touchscreen, only the keyboard, a black and white screen, a camera and an microSD. I'm not in a rush so if you can tell me where can I start learning to achieve my objective it would be great.

 

If it is not possible, what I really mind is that the camera works, so if you know how could I make that warking in that size with some devices smaller than arduino or Raspberry Pi I would be glad in the same way.

 

Thanks you community!

  • 0

    Hi Otter 4,

     

    A few years ago I successfully designed and fabricated 6 custom mobile phone prototypes for a client.

     

    I designed a control system around a PIC microcontroller and mated it with a GPRS radio modem.  There are plenty of inexpensive cell modem devices to choose from including ones from Multitech, and Telit.  I used a Multitech cell modem in my application.

    The biggest challenge I encountered was finding documentation on the sequence of events required to discover and attach to a cell network.  There are several steps you have to go through to make a connection to a cell network and a few more to send SMS messages, or process voice calls.  The documentation that comes with cell modems is usually great at explaining what each of the AT+ commands does, but you still need to know in what order to issue the commands and what to do with the various response codes.  I eventually figured the details out by doing a lot of internet searching and a bunch of disciplined trial and error coding.

     

    Another hurdle is finding a cell phone carrier that will sell you a SIM card so you can attach to their network.  I found a local carrier that was very helpful and open to the idea.  When I initially walked into the store and held up a circuit board with an antenna hanging off of it and asked if I could buy a SIM card so I could test my invention on their network, the look on the salesperson's face was a combination of utter confusion and disbelief.  After some conversation and explanation, I was allowed to buy a SIM card and get a mobile phone number.

     

    My client's application required automatic periodic upload via SMS of humidity and temperature readings,  so there was no screen, camera, or keypad for that matter. The code to run the basic SMS and voice call system with polling of humidity and temperature sensors easily fit in a PIC18F4520 running at 10 MHz.  Attaching a screen, camera, microSD, and keyboard, as described in your scenario, will require a more powerful processor.  For your application an Arduino, Raspberry Pi, or Beaglebone might work well.

     

    Mark

  • 0 in reply to Instructorman

    Hey Mark, I'm really glad.

     

    Right now I'm going to start looking for inormation about what say. I was very lost and now I know how I can start. If you don't mind I'll keep writing there or I'll message you.

     

    Thanks you so much,

     

    Otter4

  • 0

    You should take a look at entering the mangOH road test. It is aimed at cell phone IoT. The Cortex A5 would make a nice low power cell phone but still has enough computing power to do a camera. In the road test you get one to experiment with for free.

  • 0 in reply to Instructorman

    y'know... in the Libre Laptop i've developed, i have an HX8357D-based 480x272 LCD attached via its SPI interface to an STM32F072.  i got a prototyping kit from adafruit, it included a full set of libraries that allow you to do text and basic graphics, and the STM32F072 can do USB as well as UART so you'd be able to connect it to a modem and make phone calls and do SMS messages.  the adafruit kit even has an SD card on it (and a full library for reading and writing FAT filesystems) you don't *have* to go with powerful processors to do screen, microsd, keyboard, and i do know of a guy who did a 320x240 bit-banging CMOS camera on a 32-bit ARM Cortex M3, i think it was called the "followingrobot" project, it's all done as GPL-licensed code, you should be able to find it easily with a google search.  mind you, 320x240 isn't saying much image

     

    but basically, what i'm saying is: don't rule out how powerful these little embedded 72-120mhz 32-bit ARM processors really are. oh, btw, otter: do look up the Telit modem series, there's lots of people who've connected them to arduinos (like you are thinking of doing) - such as this guy: Using the Telit GE863 (GSM-GPRS module)  - i've played with telit stuff before it's absolutey superb and i know that they actually run python inside (!!!) so you can upload python scripts to them to do more complex stuff.... hilarious, right? image

     

    anyway good luck, this sounds like an awesome project, you should be able to prototype something up without needing to make a PCB really quickly - i remember firing up a Telit modem using a couple of AA batteries... don't tell noone i did that, ok?

     

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