Our design lecturer require us to come out with a black box which can differentiate between raw egg and hard-boiled egg. On the black box, there should be one inlet and two outlets (one for raw, the other for hard-boiled).Dimension constraints of the black box is 500mm x 500mm x 500mm. The power source given are 12 AA batteries (only these, no other power source are allowed), while the actuators are 3 motors (specification of the motors is up for us to decide). We have tried several ways to differentiate the eggs. The density of the egg regarding the buoyancy stuff seems not particularly useful as the density of egg is differ from one another. The only effective way we have tested to differentiate them is by spinning the egg. Nonetheless, we can hardly come out with any mechanism to spin the egg by using only three motors (not to mention transport mechanism of the egg that also require the motors). Can anyone please give some suggestions on the way of differentiating the eggs or the mechanism to spin them?