DY,
You are not understanding my question.
I do not see how the mechanism can actually do it. I am not asking halachacially, I am asking bimetzios. I am asking that if it works by the sensor sensing a pulse of light, that’s fine, the light goes on. What makes it go off? Moving the plastic in front off the sensor won’t work, because it is not a continuous beam of light, it was only intermittent. So most of the time there is no pulse of light, what is now going to make the light turn off when you move the plastic piece down again?