How to obtain a square wave from QTR-1RC?

Hi I need to know how can i get a square wave from QTR-1RC, i 'll connect on arduino’s port 2. In my tests i realise the QTR’s wave isn’t digital, so if I don’t process this wave before i connect the sensor, my circuit will not work.
TKS

How do you expect a “square wave” to work?