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Toy cash register hack to add real bar code scanner.

Picture of Toy cash register hack to add real bar code scanner.
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My daughter was disappointed that the scanner in her toy cash register didn't really work.  I solved this by interfacing an old PS/2 CueCat bar code scanner to a PIC and output the data to a serial port in ASCII format.  The original cash register display is accessed by hacking the keypad through a couple of M74HC4051 multiplexers.  The display can be cleared and the first 8 digits of the bar code displayed.   All 8 characters can be reliably written to the display in less than 250 ms.
Sweet! I bet your daughter just loves it :D