Patent ID: 8909382

Claim:
An occupancy detection system comprising: a motion detector effective to provide an output signal based on detected motion in a defined area; a sound detector effective to provide an output signal based on detected sound in the defined area; and a lighting controller effective to determine a first occupancy state based on a received motion detector output signal and a second occupancy state based on a received sound detector output signal, control one or more associated lighting devices to be turned from OFF to ON in accordance with a determined first occupancy state of ON, control the lighting devices to be turned from ON to OFF in accordance with determined first and second occupancy states of OFF for longer than a timeout period, record time stamps in association with events causing the lighting devices to be turned OFF and in association with events causing the lighting devices to be turned ON, and automatically adjust the timeout period upon receiving new time stamps based on a second order occupancy distribution analysis including each of the recorded time stamps and comprising an occupancy curve having a mean and a variance associated with a Gaussian probability distribution function, the occupancy curve being adjusted for each newly recorded set of time stamps and the timeout period being adjusted according to the mean and variance of the occupancy curve.