Abstract: A portable electronic device is provided. The portable electronic device includes a casing, a display unit, a roller, an encoder and a controller. The casing has a casing surface. The display unit is disposed on the casing surface. The roller is rotatably disposed on the casing surface with a portion of the roller being exposed outside the casing. The roller is for adjusting the voice of the portable electronic device when the portable electronic device works at a voice-adjusting mode. The roller is for touching a surface and rotating on the surface to measure a length when the portable electronic device works at a length-measuring mode. The encoder disposed inside the casing is for outputting a pulse number. The controller receives the pulse number and determines a length value accordingly, and then controls the display unit to display the length value.

Abstract: A portable electronic device is provided. The portable electronic device includes a casing, a display unit, a roller, an encoder and a controller. The casing has a casing surface. The display unit is disposed on the casing surface. The roller is rotatably disposed on the casing surface with a portion of the roller being exposed outside the casing. The roller is for adjusting the voice of the portable electronic device when the portable electronic device works at a voice-adjusting mode. The roller is for touching a surface and rotating on the surface to measure a length when the portable electronic device works at a length-measuring mode. The encoder disposed inside the casing is for outputting a pulse number. The controller receives the pulse number and determines a length value accordingly, and then controls the display unit to display the length value.