Free Fall Detection Algotithms for Hard Disk Drives

For mobile HDD, shock resistance is one of the main parameters to compare with other storage devices. One way to improve this parameter is by detecting the free fall of the consumer device and take protective measures before the impact with the ground. The new approach aims to improve the reliability of free-fall detection algorithm in broad range of real-life situations like jogging, running, dancing. The conventional approach is to measure the acceleration using the acceleration sensor and react based on acceleration threshold with timing reaction. The issue is false positive alarms, namely the detection of free fall, while there is no actual free fall. The proposed new approach is to integrate the measured acceleration to obtain the area between the acceleration threshold and the current acceleration measurement below the threshold. The detection of the free fall is performed not only depending on the acceleration, but also depending on the calculated area value.