oleasplease design this Each team will be given $5$ seconds in order to try scoring points. A countdown will appear on display segment $4$ starting from $5$ reaching to $0.$

The economical smart fan system, is a fan which automatically adjusts its RPM speed depending on the number of objects $($in this project, people$)$ in a room. The fan's speed is initially zero, and it increases linearly as a function of the number of objects in the room. The maximum speed is reached when the number of objects in the room $(N)$ is a equal to a maximum value of objects $(N\_$max$).$

Figure $1$: general setup.

An infra red $($IR$)$ sensor should be installed on the room's door and connected to the PIC microcontroller $-$ see Figure $1.$ Once a person traverses the entrance $($i$.$e$.$ enters the room through its door$)$ the IR sensor detects this event and signals it to the PIC microcontroller. The basic idea of IR object detection is illustrated in Figure $2.$ Once the PIC microcontroller detects an object, an object counter is incremented $($i$.$e$.$ NlarrN$+1.$ The speed of the motor which is already connected to the PIC microcontroller is then increased by an amount linearly proportional to the the count value.

Figure $2$: basic idea of IR object detection.

Specifically, the speed of fan's D$.$C$.$ motor is controlled via Pulse Width Modulation $($PWM$)$ according to the following equation:

$)(N_{m}ax$

where,

D: is the duty cycle of the PWM signal $(0\%--100\%.$

$N$ : number of objects in the room.

N$\_$max: maximum number of objects in the room.

The average PWM voltage $($V$\_$avg$)$ applied to the D$.$C$.$ motor is in the range of $0,V$ and is specified according to equation $(2)$:

$V_{a}vg=DxVs$

The circuit has a toggle switch. When the toggle switch is logic $0,$ the count value $(N)$ is displayed on two seven$-$segment displays and two push$-$button switches are used to modify the current speed of the motor $($UP and DOWN$)$ if needed. When the toggle switch is logic $1,$ the maximum number of objects in

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the room $($N$\_$max$)$ is displayed on the two seven$-$segment displays and the two push$-$button switches are used to modify the sensitivity of the fan $($i$.$e$.,$ increase$/$decrease the value of N$\_$max$).$

In this project, you are required to implement the functionality when the toggle switch is logic $0.$ This is a mandatory part of this project. Implementing the functionality when the toggle switch is logic $1$ is optional and is considered as bonus.