An input device includes a power unit, a power switch unit, a processing unit, and an input unit. The power switch unit includes a first switch for supplying power to the processing unit when actuated; the input unit is connected with the processing unit and the power switch unit and is configured for generating input signals that is transmitted to the processing unit and further used for controlling the first switch; and the processing unit is configured for receiving the input signal from the input unit, keeping the first switch switched on during a time period, and performing a task corresponding to the input signal during the time period.