My friend Tom recently gave me a CueCat. He told me it would read barcodes but had never actually used it. Online I discovered the CueCat had a rich history, and a lot of pages had hardware modifications or supporting code. A few if those pages are:
Electronics
22
Nov 09
The 555 Chip
The 555 Integrated Circuit (IC) chip is one of the most common ICs and is used in electronics projects by manufacturers and hobbyists alike. If you have an electronic device that has a blinking LED then there is a good chance that a 555 is being used in astable mode. Links about the 555 IC: