Patent ID: 8378855

Claim:
A control device used in a digital camera, comprising: an internal power source; a sensor comprising a stationary member and a rotatable member, the stationary member comprising a first electrode and at least two second electrodes, the rotatable member comprising a third electrode and a fourth electrode, the first electrode electrically contacting the third electrode, wherein each one of the at least two second electrodes electrically contacts the fourth electrode in sequence when the rotatable member is rotated; a shaft connecting to the rotatable member, an analysis unit configured for determining which one of the at least two second electrodes electrically contacts the fourth electrode; a control unit; wherein the control unit powers off the camera whenever the third electrode is electrically contacting the first electrode which is grounded and the fourth electrode is electrically contacting the second electrode of the at least two second electrodes that is electrically connected to the internal power which operates whenever the digital camera is powered off and powered on, the control unit powers the camera on whenever the third electrode is electrically contacting the first electrode which is grounded and the fourth electrode is electrically contacting the other one of the at least two second electrodes that is electrically connected to an external power which operates only after the digital camera is powered on, the control unit detects rotation angle of an object of the digital camera connecting to the rotatable member via the shaft according to the determination of the analysis unit.