Left to right approach (single line analysis)
 

Case 1:

         When the object enters through the plate one the Transducer produce a signal which is send to the microcontroller. The program in the microcontroller 1&2 will execute after receiving the signal which results the movement of the stepper motors at a certain angle.

        The gate is assembled with the stepper motor in such a way that with the clockwise movement of the stepper motor the gate will get closed.

Case 2:

         When the Object leave the plate two the transducer produce a signal which is sent to the microcontroller. The program in the microcontroller 3&4 will execute after receiving the signal which results the movement of the stepper motors at a certain angle.

         We program the microcontroller 3&4 in such a way that when it receive the signal from the transducer it will make the stepper motor to move anticlockwise.

         And the gate which is closed initially will open immediately.     

          

Right to left approach (single line analysis)

Case 1: