SENSOR HELP!!!

Hi everyone,

We have a project and it is called automatic garbage selector, now my problem is what type of sensor to be used in order to segregate materials such as PLASTIC, PAPER, and CAN. Does it possible to use CAPACITIVE PROXIMITY SENSOR OR IR SENSOR?

Any suggestions? :(

Optical sort.

Most optical sorters can walk and talk. Some don't

http://greenmachine.net/Green-Eye-Optical-Sorting-System.html