Thinking about the way to activate or desactivate the protective skins I realized that to stop the placement of those skins would be difficult because of the attachment of several sensors at the final of the rail that would make complex and less stronger the structure. Therefore, I will remove the internal skin. 

Seen from an energy point of view, it will reduce the energy used by one motor, however, if the skin is closed, some energy, less than the motor would use, will be consumed by the LEDs to iluminate the plant.

At the end of the rail for the skin, I will put a buttom that will be pressed by the same skin when it arrive there (closed). It sends a signal to Arduino and it stops the motor running.