US Patent 8115626 Occupancy sensing with selective emission

An occupancy sensing system includes a driver to emit energy in a space, and a sensor to detect energy reflected within the space. An electrical load for the space is controlled in response to an occupancy condition determined in response to the detected energy. The driver may be selectively de-energized. In some embodiments, the driver may be de-energized during all or a portion of an unoccupied period. In other embodiments, the driver may be de-energized during all or a portion of an occupied period. In some further embodiments, the driver may be de-energized in response to detecting other sources of the type of energy emitted by the driver.