Patent ID: 7306567

Claim:
A portable alarm system that can be worn on a user's limb, the portable alarm system comprising: a single housing that contains an accelerometer, a user interface, a display for rendering the user interface and a processing unit; the accelerometer operating to detect motion on at least one plane; the user interface enabling a user to program various alarm parameters and settings for the portable alarm system; a strap that enables the housing to be attached to a user's limb; and a processing unit, the processing unit being communicatively coupled to the accelerometer and the user interface, and in response to inputs from the accelerometer and the user interface, in cooperation with programming instructions, is operative to: receive a user selected alarm setting via the user interface, the alarm setting including an alarm time, a threshold, and a sleep cycle count; monitor the accelerometer for data indicating a positive movement of the user's limb to which the single housing is attached by means of the strap; analyzing the accelerometer data to establish the timing of sleep cycles and to identify shallow sleep periods of the sleep cycles; applying heuristics to estimate the conclusion of a sleep cycle based on sleep cycle data for the user, wherein the step of applying heuristics to estimate the conclusion of a sleep cycle based on sleep cycle data for the user further comprises the steps of: identifying a typical sleep cycle for the user; if a sleep cycle that is substantially longer than the typical sleep cycle for a user is detected, compare the duration of the long sleep cycle to the typical sleep cycle; if the long sleep cycle is approximately a multiple of the typical sleep cycle, concluding that the detection of one or more sleep cycles was missed; and incrementing the sleep cycle count in accordance with the estimated number of missed sleep cycles; and receiving a user selected mode setting via the user interface that can enable alarm modes selected from a group of alarm modes including modes for: triggering an alarm condition when a shallow sleep period of a sleep cycle occurs within a threshold prior to the alarm time; triggering an alarm condition when a shallow sleep period of a sleep cycle occurs in conjunction with the number of sleep cycles reaching the sleep cycle count; and triggering an alarm condition within a threshold after the alarm time.