Methods of smoke detecting using two different wavelengths of light and ambient light detection for measurement correction

摘要

In accordance with certain embodiments, a smoke detector determines the presence of smoke particles outside its housing based on measurements of light detected at different wavelengths and corrected based on an ambient light level.

主权项

1. A method of smoke detection utilizing a smoke detector comprising (a) a housing, (b) one or more light emitters, and (c) one or more light detectors, the method comprising:
acquiring a measurement of light including a first wavelength from a first sampling volume while emitting light of approximately the first wavelength with at least one said light emitter; acquiring a measurement of light including a second wavelength from a second sampling volume while emitting light of approximately the second wavelength with at least one said light emitter, the second wavelength being longer than the first wavelength; detecting an ambient light level outside of the housing; correcting the measurement of light including the first wavelength based at least in part on the detected ambient light level, thereby producing a corrected first-wavelength measurement; correcting the measurement of light including the second wavelength based at least in part on the detected ambient light level, thereby producing a corrected second-wavelength measurement; and determining the presence of smoke particles based on a ratio of the corrected first-wavelength measurement to the corrected second-wavelength measurement.