What does the eye in the "slide" of the Z2 do, exactly? That is, it obviously senses the presence of a paintball above it on the "slide." But, how does the circuit board use that information? It doesn't seem to start or stop the motor because on my Z2 covering the window does not stop the motor from running. That is, unless the eye is broken.
I am asking about the eye under the clear window. Part 22 on the following diagram: