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Code lock with Pic

Discussion in 'Microcontrollers' started by marcioeld, Jun 4, 2003.

  1. marcioeld

    marcioeld New Member

    Joined:
    Jun 4, 2003
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    Hi,

    I'm interesting in a low cost circuit to open/close door by programable ode (4x4 pad).
    This circuit will be used in a home automation project.
    Anybody can help me?

    regards

    Marcio
     
  2. TheAnimus

    TheAnimus New Member

    Joined:
    Jun 22, 2003
    Messages:
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    Location:
    England
    Hey re ur question. i would advise a relatively small PIC with internal EEPROM where u could store ur code, if its a dedicated PIC on a small one off jobbie (ie, ur home) then i would recomend getting a numeric keypad that is a 1*12 latice on maby a 16F870
    KISS phylisophy at play, its much simpler to code that, as on a standard numeric keypad! using portB and Cs interupt feature enabled on all pins, would make detecting a keypress simple the large 12bit counter with overflow to do that "no one has pressed a key, start looking for a code from the begging again" using the EEPROM as a simple lookup on each key press, using the EEPROM managements own indirection, ie. key press 0 would simple have to equal the byte stored at memory addres 0 for port B and memory address 1 for port C, a bit wastefull but when u have 128 bytes off it, a 64 key code would be long enough for anyone!
     
  3. Electronic boy

    Electronic boy New Member

    Joined:
    Apr 20, 2003
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    Riyadh

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