Lighting with air quality and hazard monitoring

1. A sensing and lighting device, comprising:

a lighting fixture comprising a housing and a light emitting diode (LED) light source that is at least partially in the housing and configured to emit an illumination light;

a sensor to sense air at the sensor; and

a power source that is external to the housing, wherein the LED light source and the sensor are powered by the power source, wherein the sensing and lighting device is sized to fit in a return air plenum of an air conditioning system at a location proximal to an opening of the return air plenum at a ceiling above an area to be air conditioned by the air conditioning system, and wherein the LED light source is configured to flash the illumination light to indicate a detection of a hazard condition based on a sensing of the air by the sensor.

2. The sensing and lighting device of claim 1 , wherein the sensor is positioned outside of the housing of the lighting fixture such that at least a portion of the air that flows in the return air plenum passes by the sensor from an area that is air conditioned by the air conditioning system.

3. The sensing and lighting device of claim 1 , wherein the sensor is positioned inside the housing of the lighting fixture such that at least a portion of the air that flows in the return air plenum passes by the sensor from an area that is air conditioned by the air conditioning system.

4. The sensing and lighting device of claim 1 , further comprising a wireless transmitter, wherein the wireless transmitter wirelessly transmits air quality information provided by the sensor.

5. The sensing and lighting device of claim 4 , wherein the air quality information indicates whether one or more air pollutants are detected.

6. The sensing and lighting device of claim 1 , wherein the sensor detects the hazard condition and wherein the hazard condition includes one or more of fire, smoke, carbon monoxide, and natural gas.

7. The sensing and lighting device of claim 6 , further comprising a wireless transmitter, wherein the wireless transmitter wirelessly transmits information indicating the detection of the hazard condition by the sensor.

8. The sensing and lighting device of claim 6 , further comprising a siren, wherein the siren emits a sound in response to the detection of the hazard condition.

9. A sensing and lighting device, comprising:

a lighting fixture comprising a housing and a light emitting diode (LED) light source that is at least partially in the housing and configured to emit an illumination light;

a sensor to sense air at the sensor, wherein the sensing and lighting device is sized to fit in a return air plenum of an air conditioning system at a location proximal to an opening of the return air plenum at a ceiling above an area to be air conditioned by the air conditioning system;

a driver that provides power to the LED light source; and

a control device configured to control the driver to control the power provided by the driver to the LED light source based on whether a hazard condition is detected by the sensor.

10. The sensing and lighting device of claim 9 , wherein the control device comprises a 0-10 v circuit that provides a 0-10 v dim control signal to the driver and wherein the 0-10 v circuit changes the 0-10 v dim control signal to flash a light emitted by the LED light source in response to a detection of the hazard condition by the sensor.

11. The sensing and lighting device of claim 9 , wherein the control device comprises a relay that receives an AC power signal and outputs a switched AC power that is provided to the driver and wherein the control device switches the switched AC power on and off to flash a light emitted by the LED light source in response to a detection of the hazard condition by the sensor.

12. The sensing and lighting device of claim 9 , further comprising a wireless transmitter, wherein the wireless transmitter wirelessly transmits information indicating a detection of the hazard condition by the sensor.

13. The sensing and lighting device of claim 12 , wherein the hazard condition includes one or more of fire, smoke, carbon monoxide, and natural gas.

14. The sensing and lighting device of claim 9 , further comprising a siren, wherein the siren emits a sound in response to a detection of the hazard condition.

15. A system of sensing and lighting devices, the system comprising:

a first sensing and lighting device;

a second sensing and lighting device; and

a wireless control device that wirelessly receives air quality information from the first sensing and lighting device and from the second sensing and lighting device, wherein the first sensing and lighting device and the second sensing and lighting device are each positioned in a respective return air plenum of an air conditioning system proximal to an opening of the respective return air plenum at a ceiling above an area that is air conditioned by the air conditioning system, wherein the first sensing and lighting device and the second sensing and lighting device each comprise:

a lighting fixture comprising a housing and a light emitting diode (LED) light source that is at least partially in the housing and configured to emit an illumination light;

a sensor to sense air at the sensor; and

a power source that is external to the housing, wherein the LED light source and the sensor are powered by the power source and wherein the LED light source is configured to flash the illumination light to indicate a detection of a hazard condition based on a sensing of the air by the sensor.

16. The system of claim 15 , wherein the air quality information indicates whether one or more air pollutants are detected.

17. The system of claim 15 , wherein the air quality information indicates whether a hazard condition is detected and wherein the hazard condition includes one or more of fire, smoke, carbon monoxide, and natural gas.