smart board g.The working principle of the electronic whiteboard is divided into two principles: the pressure sensing principle and the laser tracking principle. A touch-type whiteboard using the principle of pressure sensing is equivalent to a touch screen of a computer, and is a human-machine interactive input device that performs a designated work by using a finger or a pen to touch an option displayed on the screen. The electronic whiteboard has two layers of pressure sensitive film inside. When a certain point on the surface of the whiteboard is under pressure, the two layers of film cause a short circuit at this point, and the controller of the electronic whiteboard detects the coordinate value of the pressed point (touched by a finger or a pen) Location), sent to the computer via RS232 interface . A laser emitter on each side of the upper end of the whiteboard using the laser tracking principle. After the whiteboard is started, the laser emitter emits a laser to scan the surface of the whiteboard, and the special pen has an inductive laser function to feed back the position of the pen.