Need Help with a project

Discussion in 'Embedded Systems and Microcontrollers' started by nathan909, Dec 22, 2007.

  1. nathan909

    Thread Starter New Member

    Dec 22, 2007
    1
    0
    Please bear with me, as I am very new and not to literate on this stuff...

    I’m trying to make a battery powered gadget.

    Let me explain what I’m trying to do, and hopefully someone can point me in the right direction.

    This device will display text (ie Sentence).
    This device will store sentences (ie Go to the market and get some eggs.)
    This device will store up to 250 sentences in one category (ie Monday)
    This device will store 7 categories.
    You will press a button to select a category, and another to select a sentence.
    Device will have a speaker for beeps and click sounds.
    Device will need to have a USB controller to upload new categories and sentences
    I will later need help interfacing it to a computer


    I would like to use an LCD, like found here:
    http://www.crystalfontz.com/cgi-bin/pricing.pl?product=1604a
    (but I could use any other LCD)
    I need a controller to control this LCD.
    I need an IC(s) to store the text that will be displayed.
    I need an IC(s) to interface the device with a computer via USB.

    I know I will need a lot of help, which I am willing to pay for… But any suggestions on parts and who to help me prototype the device I would greatly appreciate.

    Thanks again for your time.
    -Nathan

    BTW I'm in the Southern California area.

    HughesNet Satellite Internet
     
  2. mrmeval

    Distinguished Member

    Jun 30, 2006
    833
    2
    I think the LCD you picked has the controller but the datasheet is scut crap. It doesn't tell me if you can place it into serial mode. If you can't put it into serial mode then you'd need a microcontroller with a lot of IO pins which is more money. If you're set on them then get a better datasheet and find out what controller it's mimicing, it's probably samsung or hitachi.

    Components
    Atmega168 microcontroller
    4bit LCD,
    SPI EEPROM for sentences unless you find you can store all of them and the program in the atmega168 built in flash.
    Keys: Depending on the number of keys you might need an IO expander at this point. If you don't need a lot of keys you can get away with using up the remaining digital pins and just use buttons. Much easier to code and cheaper.

    Writing the code is up to you. You'll need one more option and that would be to have code that would fill the SPI EEPROM with sentences that a blithering idiot can use. You can use processing to do that code until you can port it to Visual Basic or some other code. There will need to be a way to tell the device to get ready for new sentences and then you tell the PC to upload them to it.

    http://www.arduino.cc is the device I'm using but you could use something from atmel as well.

    I like the arduino for development but try http://www.avrfreaks.net/ for more choices.

    This is an a bit example but it eats up all the pins, you can get a shift register to drive it with three pins http://www.arduino.cc/en/Tutorial/LCD8Bits

    Much cleaner serial hookup (not rs232 serial)
    http://www.arduino.cc/playground/Learning/SerialLCD

    Extra memory for the data (not program)
    http://www.arduino.cc/en/Tutorial/SPIEEPROM

    If you need a lot of keys
    http://www.arduino.cc/playground/Main/KeypadTutorial

    This shows how to make sounds but IMHO is excessive, you can just drive a piezo beeper
    http://www.uchobby.com/index.php/2007/11/14/arduino-sound-part-2-hello-world/
     
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