Overall, there were a few things that I would have done differently if I could have a second chance with this project. 

       The first thing that I would do differently is to not spend the time trying to send the marbles down slowly using the motor and 3D printed gear.  The concept did not end up working very well because the marbles would simply spill over the sides of the gear.  

       Another thing that I would do differently is to use a lever instead of a magnet to separate the metal and wood marbles.  We attempted to use a lever, but we abandoned the idea because the magnet worked better, but the metal marbles ended up being stuck on the magnet, so they still had to be pulled off of the magnet by hand at the end instead of landing in a cup.  

       One last thing that I would do differently is to use a different idea to make the red and white marbles stop and move down one by one.  I would do this by taking the gear and motor that we used to initially send down the marbles and put it farther up the track from the line tracker.  This would allow the marbles to be stopped and sent down one by one to the line tracker, and the current motor and gear above the line tracker could hold the marble above the line tracker until the correct cup was ready for the marble.  

       Overall, I was happy with how the project turned out except for the line tracker because we could not get it to work correctly.