Portable electronic device operateable by rotation thereof

A portable electronic device comprising:

• a rotation sensor for detecting rotation of the portable electronic device and generating a signal representing the parameters of the rotation of the portable electronic device, the rotation sensor comprising:
• a supporting plate fixed to the housing;
• a cylindric carrier disposed on the supporting plate and rotatable relative to the supporting plate;
• an electron emitting device disposed on the supporting plate and located on the center axis of the cylindric carrier for emitting electrons along the center axis of the cylindric carrier;
• at least one magnet for providing a magnetic field substantially parallel to the supporting plate and fixed relative to the housing;
• a plurality of strip-shaped electrodes formed on the inner surface of the cylindric carrier for sensing the falling position of the electrons emitted by the electron emitting device;
• and
• a detecting device for detecting the falling position of the electrons and generating a signal representing the parameters of the rotation of the portable electronic device according to the change of the falling position of the electrons;
• and
• a processor electrically connected to the rotation sensor, the processor receiving the signal generated by the rotation sensor and generating an operating signal for operating the portable electronic device according to the parameters of the rotation of the portable electronic device.