| 主权项 |
1. A fall detecting device configured for detecting a fall of a user, comprising:
an accelerometer configured to be coupled to the user's torso and further configured for continuously measuring movement of the user and outputting three signals indicative of the movement of the user in three orthogonal axes, wherein each signal comprises an alternating current (AC) component representing dynamic motion and a direct current (DC) component representing static effects due to gravity; and a processor electrically coupled to the accelerometer and configured for periodically sampling the three measured signals and storing digital data indicative of the three signals in a memory, wherein the memory is electrically coupled to the processor, the processor further configured for periodically determining orientations of the user based upon the DC components of the sampled signals and changes in orientation of the user based upon the DC components of the sampled signals, the processor further configured for periodically calculating activity-induced energy expenditure (AEE) values based upon the AC components of the sampled signals and wherein AEE is a function of the AC components calculated over an integration period, the processor is further configured for determining that the user has fallen when:
(a) the processor determines that the DC components of the sampled signals indicate that the user was in a vertical position,(b) after the processor determines that the DC components of the sampled signals indicate that the user was in a vertical position, the processor determines when a first AEE value calculated from a first set of the AC components over a first integration period exceeded a first threshold, wherein the first threshold is of a magnitude that indicates activity levels that are above normal activity levels and wherein when the first AEE value calculated from the first set of AC components over the first integration period did not exceed the first threshold, the processor continues processing at (a),(c) after the processor determines that the first AEE value calculated from the first set of AC components over the first integration period exceeded the first threshold, the processor determines when the DC components of the sampled signals indicate a change in orientation of the user from vertical to horizontal and wherein when the processor does not detect a change in orientation from vertical to horizontal after a predetermined period of time, the processor continues processing at (a), and(d) after the processor determines that the DC components of the sampled signals indicate a change in orientation of the user from vertical to horizontal, the processor determines when the DC components of the sampled signals indicate a continued horizontal position and a second AEE value calculated from a second set of the AC components over a second integration period is below a second threshold, wherein the second threshold is of a magnitude that indicates activity levels that are below normal activity levels, the processor determines that a fall has occurred; and the processor is further configured to transmit an alert indicating that the fall has occurred to a central monitoring device when the processor determines that the user has fallen, and the central monitoring device is configured to provide the alert to a service provider such that the service provider may take appropriate action. |
