Many students endured a difficult and time-consuming search for an empty chair, particularly during the examination period. Furthermore, hogging seats with personal belongings for a long time are some notorious acts that are very common in the libraries. With a view to tackle these issues, this project “Find A Seat App” aims at building an application that can detect the occupancies of the seats in HKU Main Library in real-time. Two approaches, i.e. using Computer Vision techniques and Internet of Things (IoT) device, are examined and discussed in the project.