An electronic device is operated based on whether it detects vibration indicative of natural human tremors while the device is not enclosed in a small space. Human tremors are detected by sampling a motion signal and performing a discrete Fourier transformation on a plurality of sets of samples. For each sample, a mean magnitude is calculated for a first range of frequencies indicative of human tremors. A mean magnitude is also calculated for a second range of frequencies greater than the first range. If the difference between the mean magnitude of the first range and the mean magnitude of the second range, then human tremors are detected for the set of samples. Human tremors are detected for the device if a threshold number of sets of samples within a predetermined time period produce an output indicating detection.