General Workings of a barcode reader from the book “How things work”

There are four steps involved :

1- the product barcode is scanned virtually and the reader high lights the code with a red laser beam.

1- the black code, on the product, absorbs the red light. The white bar code, on the product reflects it.

3- the reflections( white codes) are read and a signal is sent to decoder. The decoder converts the bars to a binary numeric code then into a decimal code.

4- A processor compares the input decimal code to decimal codes in a database where it identifies the product.