An unfixed-position smartphone-based fall detection scheme

This paper presents a smartphone-based fall detection scheme that allows smarphones to be placed in various positions. The scheme makes no assumption of the placement of the smartphones because it is inconvenient and impractical to ask users to place their smartphones in some designated positions; therefore it does not require the users place their phones in certain fixed positions. It utilizes the built-in three-axis accelerometer in the smartphone and constantly calculates the changes of the three axes and the angels to detect fall events. Unlike other schemes that require the smartphone be placed in certain fixed positions, the proposed scheme can detect fall events when the smartphone is placed in various positions, including pockets and bags, with little misjudgment. The experiment shows the proposed scheme can achieve 91.5% in sensitivity and 97.5% in specificity.