We're constructing a robot whose basic mechanism will be lifting a box (about 18x18x18), detecting its color (either red, blue or green), then tracking a line to get to a three-path junction, where it'll read the color off a pad on the floor (again, either red, blue or green), and then follow the track to place that box in a slot of the pad's detected color.
There are basically two things we need to detect.
1. The color of the box
2. The color of the pad.
The box will likely be made of wood and spray painted.
What is the easiest and most accurate way of doing this?
Also, is it better to use IR emitter/detectors or simple color sensors?