Input devices

Input devices

1. barcode readers

   • types - UPC-A used in retail and warehousing only numbers. Code 128 used in transportation and shipment tracking, letters and numbers.
   • how?? the barcode reader has a sensor that detects reflected light from the illumination system and generates an analog signal which is sent to the decoder, which then interprets the signal and validates it.
   • dark lines have a binary value of 1 and white ones are 0

2. QR quick response

   • contain links to websites or buisness cards
   • similar to barcodes the squares reflect light differently which the phone camera can interpret and change into a website link since all of the QR codes are unique

3. 2D scanners

   • it converts a hard/paper copy document and turns it into a computer readable format
   • 1. a bright light will illuminate the document to be copied 2. a head moves across the document scanning it to produce an image that is sent to a lens 3. the focused image then falls onto a light sensitive sheet which is made of thousands of pixels which each produce