The principle of mobile phone vibration is not complex. The vibrator is made up of a micro motor and a cam (not an equal center circle), powered by cell phone batteries. When the current is input, the motor starts and the cam rotates. This is a mechanical vibration. There is a vibrating motor in it. The shaft of the motor is in the middle. Otherwise, the motor is not good enough to work. However, the motor is driven by a "half cylinder", which will not work smoothly, so it will have to vibrate. The micro motor is not so large that it can be installed.