Abstract: An input device for generating an input instruction by captured images is disclosed. The input device includes a first image capturing module, a second image capturing module and a logic control unit. The first image capturing module and the second image capturing module are disposed around a keyboard for respectively capturing a first object image and a second object image of an object and for respectively capturing a first key image and a second key image of a key on the keyboard. The logic control unit is used for calculating a first distance according to the first object image and the first key image and a second distance according to the second object image and the second key image, and for generating the input instruction when the first distance and the second distance are smaller than a first threshold value and a second threshold value, respectively.

Abstract: An interface system which is adapted to a portable device is provided. The interface system includes a control chip, a first peripheral device, an external interface port, a first, a second, a third bus driver and a control unit. The control chip provides at least a first and a second interface port. The first bus driver has a first, a second input port and an output port. The first bus driver is used to interface the first input port with the output port or interface the second input port with the output port according to a first control signal. The second bus driver is used to interface the first interface port with the external interface port or interface the output port with the external interface port according to a second control signal. The third bus driver is used to interface the first peripheral device with the second input port or interface the second interface port with the first peripheral device according to the first control signal.