An electronic appliance includes a display. A screen of the display on which an image from a video camera is displayed is divided horizontally by N and vertically by M, to define a plurality of detection zones. A detection unit of the electronic appliance includes detectors assigned to the detection zones, respectively. In response to a motion conducted by an operator, the detectors generate first detection signals. From the first detection signals, a signal generator of the electronic appliance generates second detection signals. Each of the second detection signals is accumulated. If any one of the cumulative values exceeds a threshold, a flag is set. A plurality of detectors including the detector related to the flag-set cumulative value are chosen to receive timing pulses from a timing pulse generator.