What is QR code actually and how it works?

 QR codes are a technology that desperately wants our attention. They appear everywhere from supermarket shelves and magazines to hiking trails and tombstones.

QR (Quick Response) code is the trademark name for the two dimensional barcode system. It was originally invented in 1994 by Denso Wave, a Toyota subsidiary, as a way to track vehicles as they were assembled, and to scan components at high speeds. While Denso Wave does hold the patent on the technology, it has granted free licence on it, going so far as to publish the spec online, and allowing anyone to use it.

The conventional one dimensional barcodes used on virtually every consumer product are mechanically scanned. That is, they're read by physically bouncing a narrow beam of light onto the code, which can be interpreted using the pattern of light reflected off the white gaps between the lines.