Design a sensor-based system - document ideas

Assignment details: Your task is to design a sensor-based system to determine the direction of travel (IN or OUT) of people through a standard sized doorway. 1) What main challenges are present for this application? 2) What sensors and sensory method would you use? Show how your solution would work. 3) Your solution will be integrated into a larger system for remote monitoring. List the primary components required to integrate your solution into the larger system (hardware and/or software) and describe their function. Produce a system architecture diagram detailing all interconnections from your solution to the larger system. 4) What are the benefits of your solution? Are there any limitations? If so, how could these limitations be addressed? Please document any assumptions that you have made.