This disclosure relates to detecting non-meaningful motion with a portable device. In one aspect, a suitable method includes detecting motion with a portable device by obtaining inertial sensor data representing motion of the portable device, wherein the inertial sensor data includes accelerometer data and gyroscope data, processing the accelerometer data, processing the gyroscope data and identifying non-meaningful motion of the portable device based, at least in part, on the processed accelerometer data and the processed gyroscope data.