There is something on the ceiling of the hotel that rings every once in a while. Why?

There are usually mice in hotels. If there is regular noise, it may be the disturbance of air conditioning or elevator to the ceiling. You can inform the front desk to change rooms. If you don't want to change rooms, you can call the front desk to ask for cleaning or safety inspection. If the pile is ignored, you can call the head office or 123 15 to complain.