[MagiChau]

For me I see it is vital instead for that human player, the feeder, to have a good grasp of knowing what tube to give by looking at the tubes already scored, where the uber-tubes are, and what tubes other robots from the alliance are currently carrying or picking up etc.

In case plans need to be changed perhaps you could make the robot do certain motions with the arm or drive-train to indicate what tube as it goes into the lane.

It appears that the robot must make the signal to me though there is always the chance the wrong signal is given.