Yes. Was looking for something similar to the garage door IR sensor. A garage door unit may seem overkill for two reasons: 1. Beam would need to span less than 20 mm (less than 1 inch) across to work. 2. the part that falls through the tube is less than 9mm across, so it may not block all the IR beam. Im going to explore options for smaller scale IR sensors.
Since part of the problem is that anything in the tube causes hang-ups with the dropped items, my idea would be for something to function through the clear tube without having to cut or shape the tube in any way. I am even looking at some sort of IC that uses radar, inductive proximity sensors, laser, etc.