QR codes

They come to us from Japan where they are very common. QR is short for Quick Response (they can be read quickly by a cell phone). They are used to take a piece of information from a transitory media and put it in to your mobile phone or tablet. Previously you need to download a qr code reader to your telephone from Google Play, for example QR droid. 
We can generate a qr code from a plain text, a url, a sms, a telephone, a location etc. We can use some qr code generator free from the Internet (unitag, qrcode kaywa).

Here I let you a prezzi presentation where you can see school project with qr codes