QR Codes (Quick Response) are two-dimensional matrix barcodes. They were originially developed by Denso Wave, a subsidiary of Toyota, back in 1994 to track vehicles during the manufacturing cycle.
QR Codes are very easy to make and are read very quickly by QR Code readers vs. standard bar codes.
Most smart phones have apps available to decode a QR Code using the smart phone's camera.
QR codes are getting more and more popular in every area. You see them in magazines, schools, ads, and more. They are even on your computer screen. They are usually used for URL's to direct someone to a web page. They are even being used for business cards. You keep one card with the QR code, or keep it on your smartphone and then someone else just scans it with theirs.
I've been using them more often lately as they are more popular and I just generated some for the links to my class web sites and blogs since many of my students have smart phones now.
The QR Code generator I've been using is Kaywa's. Easy to use and free. Simply enter the data, select the size, and hit generate. You can create a QR code for a URL (web site address), text, SMS (text message) or even a phone number.
Teachers are using them instead of writing out URLs and other info. Some teachers even make scavenger hunts using them.
They are a fun and useful way to share information.
A few QR Code Generators:
Goo.gl - Google's url shortener, also create's QR Codes. After you enter the URL and shorten it, click on "details" to see the QR Code. The goo.gl extension for Chrome will also quickly create a QR Code for you. It's probably the easiest QR Code generator.
A few QR Code Readers:
Android - QR Droid
Web based decoder (enter image url or upload image of QR Code)
MiniQR (also capture image with webcam)
iOS - QR Reader for iPhone, iPad, iPod Touch
Blackberry QR Code Scanner
Windows Mobile QR Code Reader
HP/Palm webOS QR deCODEr
How do you use QR Codes?