Electrical Engineering - Digital Logic Question

Please a design a State Diagram and Synchronous Digital Circuit (Use D Flip-Flops: no reset/preset) for a simple elevator system.

Input: Elevator Button, Human Sensor Output: Status of Elevator's Door (000: closed, 001: 20% open, 010: 40%, 011: 60%, 100: 80%, 101: open)

- When the button is pressed, the elevator door opens. - The door remains open for 10Counts. - It takes 5Counts for the door to open. ex) 1Count to open 20%. - If nobody is detected for the next 3Counts, door starts to close. - But if somebody is detected for the next 3Counts, door remains open for extra 3Counts. This process can be repeated until the Count since door opens is at 20Count. After 20Counts, the door will start to close.

While Door is Closing - If somebody is detected, door opens, stays open for 3CLK. - After the above process repeats 3 TIMES, and somebody is detected again, the door stops closing and waits until it senses nobody.