Human Localization and Activity Detection Using Thermopile Sensors

We describe a method of using simple thermopile sensors to locate a person within a given space. In order to achieve localization, several sensor nodes were placed along the walls of a room. At any given time, a person would be in the view of at least one of the sensor nodes. An algorithm is used to calculate the distance of a person from the sensor node based on its temperature reading. By combining the sensor readings from the distributed nodes, the location of the person can be estimated. This method is immune to lighting changes in the room and can even work in the dark. Additionally, we show that this method of sensing can also detect events such as a person walking past the doorway to a room, lingering outside, and entering or leaving the room. prime concern. By inspecting the sensor information, we can determine that movement of an elderly person has not been detected within a certain time interval and an alert can be sent to the health care provider. There are several localization methods [2] that have been proposed by the research community and commercial systems are beginning to emerge. Broadly speaking, the different localization techniques can be classified into two categories depending on whether or not the user has to wear a sensing device or is required to carry a tag. In the first category, we have active RFID [3], infrared [4], and ultrasonic [5] tags. In these methods the tags function either as a beacon or a listener and use time-of-flight (TOF), time difference of arrival (TDOA) or angle of arrival (AOA) measurements to triangulate the location.