A system for determining a configuration of one or more occupants in a space, comprising: at least one sensor device comprising a single-pixel thermopile in the space, wherein the single-pixel thermopile is configured to capture sensor signals related to one or more occupants in the space; a controller in communication with the at least one sensor device in the space, wherein the controller is configured to: determine or obtain training data for detecting first and second configurations of one or more occupants in the space; receive a temperature signal from the single-pixel thermopile, the temperature signal corresponding to a detection area in the space that is within a field-of-view of the single-pixel thermopile over time; detect a change in the temperature signal, the change being equal to or larger than a predetermined step threshold; determine first and second probabilities for at least one feature of a shape or pattern of the temperature signal, the first and second probabilities corresponding to the first and second configurations of the one or more occupants in the space based on the training data, respectively; and identify a class label for the temperature signal using the determined first and second probabilities and a posteriori probability estimate, wherein the class label corresponds with the first or second configurations of the one or more occupants in the space and wherein the posteriori probability estimate indicates the first probability or the second probability. at least one sensor device comprising a single-pixel thermopile in the space, wherein the single-pixel thermopile is configured to capture sensor signals related to one or more occupants in the space; a controller in communication with the at least one sensor device in the space, wherein the controller is configured to: determine or obtain training data for detecting first and second configurations of one or more occupants in the space; receive a temperature signal from the single-pixel thermopile, the temperature signal corresponding to a detection area in the space that is within a field-of-view of the single-pixel thermopile over time; detect a change in the temperature signal, the change being equal to or larger than a predetermined step threshold; determine first and second probabilities for at least one feature of a shape or pattern of the temperature signal, the first and second probabilities corresponding to the first and second configurations of the one or more occupants in the space based on the training data, respectively; and identify a class label for the temperature signal using the determined first and second probabilities and a posteriori probability estimate, wherein the class label corresponds with the first or second configurations of the one or more occupants in the space and wherein the posteriori probability estimate indicates the first probability or the second probability. determine or obtain training data for detecting first and second configurations of one or more occupants in the space; receive a temperature signal from the single-pixel thermopile, the temperature signal corresponding to a detection area in the space that is within a field-of-view of the single-pixel thermopile over time; detect a change in the temperature signal, the change being equal to or larger than a predetermined step threshold; determine first and second probabilities for at least one feature of a shape or pattern of the temperature signal, the first and second probabilities corresponding to the first and second configurations of the one or more occupants in the space based on the training data, respectively; and identify a class label for the temperature signal using the determined first and second probabilities and a posteriori probability estimate, wherein the class label corresponds with the first or second configurations of the one or more occupants in the space and wherein the posteriori probability estimate indicates the first probability or the second probability.