JarkkoL, I thought about dc motors but I need to control perfectly the angle of the rotation, then I guess this is not the case, nor I want to use any sort of encoder. We still don't know the budget, we just hope that the client can afford €7-8k for everything, the hardware and our work.
Robin2, the objects will be plastic cylinders, the size is still in discussion but the diameters should'n be bigger than 5 cm and the height not more than 7 cm.
They are arranged in a matrix, fixed to a sort of metal grid trough very long shafts. The segments are aligned horizontally. Probably they won't have any bearings, they cost to much for the budget.
Yes I'm able to realize small mechanical parts, I can also use a 3d printer or a laser cutter or my own hands!
yes is a pretty fun project