A building automation system comprising: a first monitoring device (102-1, 202-1, 302-1) having a housing comprising a body and a cap, wherein the cap comprises a plurality of windows (946, 948A, 948B, 950), wherein at least some of the windows are infrared transparent, and wherein the housing contains: a) a first sensor (830-1, 830-2) of a first group of sensors, wherein the first group of sensors include sensors configured to monitor a state of the first monitoring device and provide first data representative thereof; b) a second sensor of a second group of sensors, wherein the second group of sensors includes sensors configured to monitor a state of the first monitoring device's ambient environment and provide second data representative thereof; c) a processor configured to generate a first message based on at least one of the first data and the second data; and d) a transmitter configured to transmit the first message; wherein the second sensor is an active infrared sensor configured to detect the direction of nearby motion, the active IR sensor comprising a first near-IR light-emitting diode, a second near-IR light-emitting diode, and a first receiver configured to detect near-IR, wherein: i) the first near-IR LED is positioned in the housing and with respect to the cap so that near-IR radiation emitted therefrom escapes from a first window of the plurality thereof, ii) the second near-IR LED is positioned in the housing and with respect to the cap so that near-IR radiation emitted therefrom escapes from a second window of the plurality thereof, and iii) the first receiver is positioned in the housing and with respect to the cap so that near-IR radiation entering the housing through a third window of the plurality thereof is received by the first receiver. a first monitoring device (102-1, 202-1, 302-1) having a housing comprising a body and a cap, wherein the cap comprises a plurality of windows (946, 948A, 948B, 950), wherein at least some of the windows are infrared transparent, and wherein the housing contains: a) a first sensor (830-1, 830-2) of a first group of sensors, wherein the first group of sensors include sensors configured to monitor a state of the first monitoring device and provide first data representative thereof; b) a second sensor of a second group of sensors, wherein the second group of sensors includes sensors configured to monitor a state of the first monitoring device's ambient environment and provide second data representative thereof; c) a processor configured to generate a first message based on at least one of the first data and the second data; and d) a transmitter configured to transmit the first message; a) a first sensor (830-1, 830-2) of a first group of sensors, wherein the first group of sensors include sensors configured to monitor a state of the first monitoring device and provide first data representative thereof; b) a second sensor of a second group of sensors, wherein the second group of sensors includes sensors configured to monitor a state of the first monitoring device's ambient environment and provide second data representative thereof; c) a processor configured to generate a first message based on at least one of the first data and the second data; and d) a transmitter configured to transmit the first message; wherein the second sensor is an active infrared sensor configured to detect the direction of nearby motion, the active IR sensor comprising a first near-IR light-emitting diode, a second near-IR light-emitting diode, and a first receiver configured to detect near-IR, wherein: i) the first near-IR LED is positioned in the housing and with respect to the cap so that near-IR radiation emitted therefrom escapes from a first window of the plurality thereof, ii) the second near-IR LED is positioned in the housing and with respect to the cap so that near-IR radiation emitted therefrom escapes from a second window of the plurality thereof, and iii) the first receiver is positioned in the housing and with respect to the cap so that near-IR radiation entering the housing through a third window of the plurality thereof is received by the first receiver. i) the first near-IR LED is positioned in the housing and with respect to the cap so that near-IR radiation emitted therefrom escapes from a first window of the plurality thereof, ii) the second near-IR LED is positioned in the housing and with respect to the cap so that near-IR radiation emitted therefrom escapes from a second window of the plurality thereof, and iii) the first receiver is positioned in the housing and with respect to the cap so that near-IR radiation entering the housing through a third window of the plurality thereof is received by the first receiver.