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brulejr / ArduinoSecuritySystem

Arduino-based Security System
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Add ability to set security code via keypad #4

Closed brulejr closed 12 years ago

brulejr commented 12 years ago

System should keep the security code in some sort of permanent memory (e.g. EEPROM) outside of the firmware. A system setting (DIP switch) should allow this code to be changed but only when the setting is enabled.

brulejr commented 12 years ago

The ATmega328 chip has 1024 bytes (1k) of built-in EEPROM that can be accessed using the standard Arduino EEPROM library. Due to internal limitations, one can only store 8-bit numbers (one byte) in the EEPROM. This limits the decimal value of the number to fall between zero and 255 without further algorithms.

brulejr commented 12 years ago

A good article on using the internal Adruino EEPROM..

http://tronixstuff.wordpress.com/2011/03/16/tutorial-your-arduinos-inbuilt-eeprom/

brulejr commented 12 years ago

Need to figure out how to read / write multi-byte key to EEPROM with single-byte mode data paradigm.