Here is the actual assignment:
The process consists of a parking garage with an entrance and an exit door. The garage has 25 parking spaces. We assume the garage is empty at the beginning of the day. The parking garage manager starts the operation by pressing an NO pushbutton. As soon as the process starts, a green light turns on at the entrance of the garage indicating that parking space is available. The number of parking vehicles in the garage is constantly monitored as vehicles enter or exit the garage. To indicate that a vehicle has entered the garage, an NO pushbutton is pressed. Another NO pushbutton is pressed if a vehicle leaves the garage. If the number of parked vehicles in the garage is 23 or 24, the green light is turned off and a yellow light flashes continuously at the rate of one second on and one second off, indicating that the garage is getting almost full. If the garage is full, the flashing yellow light turns off and a red light turns on indicating that the garage is FULL. At this point if one or two vehicles leave the garage, the red light turns off and the flashing yellow light turns on. If additional vehicles leave the garage, the flashing yellow light turns off and the green light is turned back on.
For safety issues, the manager of the parking garage has decided not to allow any vehicle entering the parking garage if it is raining. When it rains, the red light should turn on at the entrance indicating the garage is full (even though it may not be full). The red light should be on for the duration of rain even if all cars leave the garage. When rain stops, normal operation resumes. Construct and incorporate a moisture sensor to simulate rain when the sensor is sprayed with salt water. At the end of the day, a NC pushbutton is pressed to stop the process and reset all counters.
