Rotation sensing device and portable electronic device having the same

A portable electronic device comprising:

• a main body;
• and
• a rotation sensing device set inside the main body, the rotation device comprising a capacitor module, wherein, the capacitor module comprises a upper substrate and a lower substrate;
• the upper substrate comprises a plurality top plates mounted thereon, the lower substrate comprises a plurality bottom plates mounted thereon, each bottom plate corresponding to one of the top plates;
• a pointing module comprising a pointer rotatably set between the upper substrate and the lower substrate;
• wherein the pointer is magnetic and comprises a first portion, when the pointer rotates relative to the capacitor module, the first portion has an initial position between a bottom plate and a corresponding top plate;
• and
• a detection circuit electronically connected to the top plates and the bottom plates, and configured for detecting pulses caused by a change in the capacitance resulting from movement of the capacitor module, and determining a position change of the first portion relative to the initial position according the detected pulses, and determining a rotation orientation of the capacitor module according to the determined position change.