Patent attributes
A sensor may be configured to determine how many people that have entered or exited a space. The sensor may comprise a pyroelectric infrared (PIR) detection circuit capable of generating different output signal patterns in response to a person entering or exiting the space. The sensor may determine whether the person has entered or exited the space based on the output signal pattern. The sensor may include a thermopile array, a radar detection circuit, or a visible light sensing circuit. The thermopile array, radar detection circuit, or visible light sensing circuit may be capable of detecting a person's location and/or movements within an area monitored by the sensor and determining, based on the detected movements, whether the person has entered or left the space. An occupant count of the space may then be determined accordingly by the sensor or by a system controller.