Problem (see video) :
Solution 1 : The photocell is too far (width) compared to the shuttlecok, so you have to push the photocell in direction to the robot.
Solution 2 : The shuttlecock is too high compared to the photocell, so you have to downside the shuttlecock.
If Solution 1 or Solution 2 doesn’t fix the problem, follow the Solution below :
Solution 3 : thighten the screw as seen on the photos below
Solution 4 : Drill four holes in the clamps of the robot and add 4 screw.