Pre-impact & impact detection of falls using wireless Body Sensor Network

Falls in elderlies are a major health and economic problem. This paper aimed at finding the best body position to place inertial sensors and the best feature for pre-impact and impact detection of fall using wireless Body Sensor Network. Waist acceleration maybe the optimal formula for fall detection, under the conditions of existing inertial sensor's best precision. We set two thresholds for acceleration, 5 m/s
²
could get 500ms lead-time and 35 m/s
²
ensure the specificity up to 100%. We also analyzed the critical phase in fall events, and subdivided it into three periods, make a fall event more intuitive to people.