Arduino-based Point-of-sales system 

I made a point-of-sales system using Arduino, a receipt printer, a 20x4 LCD and a keyboard
 on October 13, 2012. I thought it would be a good exercise for me because I really wanted
 a reason to use the Adafruit receipt printer and I would have an example of an embedded 
 systems project that was complicated enough to require a state machine. I've documented 
 all the hardware and software at:
 
 http://speedysignals.wordpress.com/2012/11/22/arduino-based-point-of-sales-system/
 
  Dependencies (libraries used)
  ------------
  
  Adafruit Thermal Printer Library
  Adafruit DS1307 Library
  LiquidCrystal Library
  PS2 Keyboard Library
  MemoryFree Library
  Streaming
  Arduino 1.0
  
  Authors
  -------
  
  Andrew Ong