Motor Marble Run Tile

I made a self-contained motor marble run tile with ferris-wheel-like wheel that carries the marble to the top, and the marbles slide down either to right or left . The photointerruptor sensor is located in the path where at least three marbles line up to enter the wheel. The challenging part of making this was making the marbles enter the wheel while the wheel is spinning. Making the marbles exit out on the top and slide down was difficult too. The solution to this was making the motor spin a lot slower and making the front part of base slightly elevated so that marbles slide into holes. In order to fully utilize the function of the photointerruptor sensor, I could have placed it right in front of the entrance hole of the wheel. Overall, I am happy with how it works after fixing the dc motor speed and slope of the base.