A portable device and a method for providing a voice recognition service are disclosed. The portable device includes a mechanical vibration sensor configured to sense vibrations having a magnitude equal to or larger than a threshold and generate an electrical signal, a motion sensor configured to sense a motion of the portable device, an audio sensor configured to receive a voice command, a sensor hub configured to control a plurality of sensors including the motion sensor and the audio sensor, and a main processor configured to execute an application and control the portable device. When the portable device is placed in standby mode, upon receipt of the electrical signal from the mechanical vibration sensor, the sensor hub is configured to switch from inactive state to active state and activate the motion sensor.