Patent attributes
A car door opening pre-detection system for a car includes a first detecting module, a second detecting module and a control module. The first detecting module is installed within the car. The first detecting module issues a motion detecting signal according to a result of detecting a motion of a palm. The second detecting module is installed outside the car. When the car is stopped, the second detecting module is enabled to selectively provide a first detection range or a second detection range. The control unit judges whether a car door of the car is about to be opened according to the motion detecting signal. When the car is stopped and the control module judges that the car door is about to be opened, the second detecting module provides the second detection range to detect whether there is a moving object behind the car.