Problem $3|14$ points

Apple packaging System

Product packaging is one of the most frequent cases for automation in industry. It can be encountered with small machines $($ex$.$ packaging grain like food products$)$ and large systems such as machines for packaging medications.

The presented machine in the figure below solve the counting issue when incorporating a specific number of apples to be packed in one box. The machine is controlled by $2$ momentary buttons $($start $\backslash$& stop$),$ each button is equipped with a LED to indicate the state of the machine $($start $\backslash$& stop LEDs$).$

Machine operation:

$-$ When the start button is pressed the start LED is turned on and the machine starts working. The start LED will turn off when the stop button is pressed.

$-$ When the stop button is pressed the stop LED is turned on and the machine starts working. The stop LED will turn OFF when the start button is pressed.

$-$ MB$1$ starts when there is no box at LS$1$ sensor and if the box is full.

$-$ MB$2$ is ON when there is a box at LS$1$ and if the box is not full.

$-$ IR$1$ is used to count the number of apples.