I have seen those sorting machines, where the the roulette dealer puts all the losing roulette chips down a hole in the table, and then a machine automatically sorts them by color. This cuts down on having to use a 2nd person during busy times.

My question is how does the machine know which color is which for sorting purposes? Are they microchipped? Does each chip weigh slightly different? Can the sorter "see" the different colors to sort.

Just wondering..