APPARATUS AND METHOD FOR DETECTING THE PRESENCE OF WATER ON A REMOTE SURFACE

• US 20120140233A1
• Filed: 12/07/2011
• Published: 06/07/2012
• Est. Priority Date: 12/07/2010
• Status: Active Grant

• Current Assignee: Techwell Consulting LLC
• Original Assignee: Techwell Consulting LLC
• Inventors: Roddy, James E., Rockwell, Thomas L.
• Granted Patent: US 8,796,627 B2
• Time in Patent Office: Days
• US Class Current: 356/445
• CPC Class Codes: G01N 21/4738 Diffuse reflection precedence is given to G01N21/55 - G01N21/57 if specular component is taken into consideration, e.g. also for testing fluids, fibrous materials
• CPC Class Codes: G01N 21/55 Specular reflectivity

Abstract

An apparatus is provided having a source for illuminating a remote surface with at least one wavelength of light (e.g., in the range of 940 to 970 nm), a detector for receiving returned illumination from the surface and providing an analog signal representative of the returned illumination, and a controller which samples the analog signal to obtain sample data representative of amplitude of light of the source returned from the surface by the detector. The controller determines the presence of water (or moisture, liquid, ice, vapor or heavy gases) on the surface in accordance with the sample data. An audible alarm is activatable by the controller. The source and detector are in a housing in perpendicular or non-perpendicular orientations with respect to the surface. Such housing being mountable at a distance from the surface where water detection is desired.

Claims

1. An apparatus for detecting moisture, liquid, ice, vapor or heavy gases upon a surface comprising:

a source for illuminating a surface with at least one wavelength of light;

a detector for receiving returned illumination from said surface and providing an analog signal representative of said returned illumination;

a controller which samples said analog signal to obtain sample data representative of amplitude of light of said source returned from said surface by said detector, and said controller determines the presence of moisture, liquid, ice, vapor or heavy gases, on said surface in accordance with said sample data;

a housing mountable in a home or building having at least said source, detector, and controller, and said housing is at a distance from said surface, wherein said illumination is projected by said source from said housing along a first direction to illuminate a first region along said surface, and said detector receives return illumination at said housing along a second direction from a second region along said surface, in which said first region and said second region are the same or substantially overlap along said surface; and

said detector is operable to provide said analog signal enabling said controller to obtain said sample data for use in determining the presence of moisture, liquid, ice, vapor or heavy gases on said surface when said first direction and said second direction are each perpendicular with respect to said surface and when said first direction and said second direction are each non-perpendicular with respect to said surface.

2. The apparatus according to claim 1 wherein said source is driven at an oscillation frequency to modulate the illumination from said source, and each sample of said analog signal by said controller is captured at a time in accordance with said oscillation frequency to minimize the effect of any ambient light received by said detector in said signal.

3. The apparatus according to claim 2 wherein said oscillation frequency has alternating peaks of a different sign (+ and −

), and said controller determines each time said signal corresponds to when said source was driven at said peaks and samples the analog signal at each said time to obtain said sample data representative of the amplitude of said analog signal.

4. The apparatus according to claim 3 wherein said sample data for each sample of said analog signal represents an absolute difference of the amplitude of said signal when sampled and the amplitude of said analog signal when previously sampled.

5. The apparatus according to claim 2 further comprising a quadrature detector for determine the difference in phase between the oscillation frequency of the source and the detected oscillation frequency of the return analog signal, and said sampling by said digital detector is offset by said difference in phase.

6. The apparatus according to claim 5 wherein said quadrature detector is part of the controller.

7. The apparatus according to claim 1 wherein specular reflection of said illumination in said returned illumination from said surface is avoided when said first direction and said second direction are non-perpendicular with respect to said surface, and said first direction and said second direction are at a common angle or different angles with respect to the normal of said surface.

8. The apparatus according to claim 1 wherein said controller determines the presence of moisture, liquid, ice, vapor or heavy gases in accordance with said sample data having a representative value in a period of time below a first threshold value, and said controller determines a fault condition in accordance with said sample data having a representative value in a period of time above a second threshold value, in which said fault condition prevents detection of moisture, liquid, ice, vapor or heavy gases by said controller.

9. The apparatus according to claim 8 further comprising memory, wherein said controller stores sample data in said memory, and determines the presence of moisture, liquid, ice, vapor or heavy gases in accordance with an average value of a plurality of said sample data stored in said memory over a period of time being below said first threshold to avoid false detection of moisture, liquid, ice, vapor or heavy gases by said controller.

10. The apparatus according to claim 8 wherein said first and second thresholds are set by said controller in accordance with sample data when said first region and second region along said surface is dry.

11. The apparatus according to claim 1 wherein said source is an LED operative at a wavelength in a range of 940 nm to 970 nm.

12. The apparatus according to claim 11 wherein detector comprises a phototransistor or LED for use as an illumination receiving element for detecting the amount of said returned illumination.

13. The apparatus according to claim 1 wherein said surface represents a first surface, and said housing is mounted on a second surface at said distance from said first surface.

14. The apparatus according to claim 13 wherein said first surface represents the surface of a floor of a building or room, and said second surface represents the wall or ceiling of said building, room, or basement.

15. The apparatus according to claim 1 further comprising an audible alarm in said housing which is activated by said controller when said controller determines the presence of moisture, liquid, ice, vapor or heavy gases on said surface.

16. The apparatus according to claim 1 wherein said controller controls the operation of said source, said controller operates in at least a measurement mode and a sleep mode, said source is enabled by said controller in said measurement mode, said source is disable by said controller in said sleep mode, and said controller alternates between said measurement mode and sleep mode.

17. The apparatus according to claim 16 wherein said controller operates in said sleep mode for a first period of time, and when said controller determines the presence of moisture, liquid, ice, vapor or heavy gases in accordance with said sample data during said measurement mode said controller operates in said sleep mode for a second period to time shorter than said first period of time to increase the rate said controller alternates between said measurement mode and sleep mode.

18. The apparatus according to claim 17 wherein after a certain number of alternating measurement mode and sleep mode periods at said increased rate said controller has determined the presence of moisture, liquid, ice, vapor or heavy gases in accordance with said sample data, said controller activates an alarm indicative of the presence of moisture, liquid, ice, vapor or heavy gases on said surface, otherwise said controller reset said sleep mode to said first period of time.

19. The apparatus according to claim 1 further comprising first optics for directing the illumination from said source to said surface

20. The apparatus according to claim 19 wherein said optics comprise one or more of a parabolic reflector, a lens, or a filter.

21. The apparatus according to claim 19 wherein said optics comprises one of a glass lens, a molded plastic lens, a Fresnel lens, a cylinder lens, a prism or a combination thereof

22. The apparatus according to claim 19 wherein said optics comprises one or more cylinder lenses or prisms for forming a line beam on said surface.

23. The apparatus according to claim 19 wherein said optics represents first optics, and said apparatus further comprising second optics for collecting return light from said surface to said detector, and said first optics are identical to said second optics.

24. The apparatus according to claim 1 further comprising one or more optical elements for filtering illumination from one or more of said source and said detector.

25. The apparatus according to claim 1 wherein the detector comprises an illumination receiving element and a receiver which operates to provide said analog signal responsive to the amount of light being collected by said illumination receiving element.

26. The apparatus according to claim 25 wherein said source is driven at an oscillation frequency to modulate the illumination from said source, and each sample of said analog signal by said controller is captured at a time in accordance with said oscillation frequency, wherein said source and detector are each an LED, and said receiver comprises a synchronous detection circuitry synched to said oscillation frequency.

27. The apparatus according to claim 25 wherein said illumination receiving element is a photodetector, and wherein said receiver comprises a synchronous detector, and said source is a modulated LED synchronized with said circuitry.

28. The apparatus according to claim 27 wherein said photodetector is one of a photodiode, a phototransistor, an avalanche photodiode, or a photomultiplier.

29. The apparatus according to claim 1 further comprising a visible LED or visible laser pointer in said housing which when operated by said controller is used to align said first direction and second direction at a location on said surface.

30. The apparatus according to claim 1 wherein said source represents a plurality of sources each providing illumination at the same or different wavelengths.

31. The apparatus according to claim 1 wherein said source represents a plurality of sources of a plurality of different wavelengths, and detector represents a plurality of detectors at said plurality of wavelengths each providing a different one of said analog signal which is sampled by said controller to provide sample data for each one of said plurality of wavelengths.

32. The apparatus according to claim 31 wherein said controller determines a ratio of two values each representative of sample data associated with a different one of said plurality of wavelengths to determine the condition and type of fluid on the surface.

33. The apparatus according to claim 30 wherein the sources are at different angles with respect to each other.

34. A method for detecting of moisture, liquid, ice, vapor or heavy gases on a surface comprising the steps of:

illuminating a surface with at least one wavelength of light along a first direction to said surface in which said source is driven at an oscillation frequency;

detecting returned illumination from said surface along a second direction from said surface to provide an analog signal representative of said returned illumination;

sampling said analog signal to obtain sample data representative of amplitude of light of said source returned from said surface onto said detector in which the time of capture of each sample of said analog signal by said controller is in accordance with at least said oscillation frequency to diminish effect of any ambient light received by said detector present in said signal; and

determining the presence of moisture, liquid, ice, vapor or heavy gases in accordance with said sample data, wherein said detecting step is operable to provide said analog signal enabling said determining step to be carried out when said first direction and said second direction are each perpendicular with respect to said surface and when said first direction and said second direction are each non-perpendicular with respect to said surface.

35. The method according to claim 34 further comprising the step of providing an alarm signal when the presence of said moisture, liquid, ice, vapor or heavy gases is determined.

36. The method according to claim 34 wherein said determining step further comprising the steps of:

determining in accordance with a first threshold when said sample data indicates the presence of moisture, liquid, ice, vapor or heavy gases; and

determines in accordance with second threshold when said apparatus is in a condition preventing detection of moisture, liquid, ice, vapor or heavy gases.

37. The method according to claim 34 wherein said illumination step provides illumination in the range of 940 to 970 nm.

38. An apparatus for detecting moisture, liquid, ice, vapor or heavy gases upon a surface comprising:

a source for illuminating said surface with at least one wavelength of light;

a detector for receiving returned illumination from said surface illuminated by said source and providing an analog signal representative of said returned illumination;

a controller which samples said analog signal to obtain sample data representative of amplitude of light of said source returned from said surface by said detector, and determines in accordance with a first threshold when said sample data indicates the presence of moisture, liquid, ice, vapor or heavy gases, and determines in accordance with second threshold when said sample data indicates a fault condition preventing detection of moisture, liquid, ice, vapor or heavy gases.

39. An apparatus for detecting moisture, liquid, ice, vapor or heavy gases upon a surface comprising:

a source for illuminating said surface with at least one wavelength of light in which said source is driven at an oscillation frequency to modulate the illumination from said source;

a detector for receiving returned illumination from said surface and providing an analog signal representative of said returned illumination;

a controller which samples said analog signal to obtain sample data representative of amplitude of light of said source returned from said surface by said detector in which the time of capture of each sample of said analog signal by said controller is in accordance with at least a synchronous detector aligned with the peaks of said oscillation frequency by a quadrature detector to diminish effect of any ambient light received by said detector present in said signal; and

said controller determines the presence of moisture, liquid, ice, vapor or heavy gases in accordance with said sample data.

40. An apparatus for detecting moisture, liquid, ice, vapor or heavy gases upon a surface comprising:

a source for illuminating said surface with at least one wavelength of light;

a detector for receiving returned illumination from said surface and providing an analog signal representative of said returned illumination;

a controller which samples said analog signal to obtain sample data representative of amplitude of light of said source returned from said surface onto said detector; and

said controller controls the operation of said source and said detector, said controller operates in at least a measurement mode and a sleep mode, said source is enabled by said controller in said measurement mode for a first period of time, said source is disabled by said controller in said sleep mode for a second period of time, said controller alternates between said measurement mode and sleep modes, said first time period is less than said second time period, and said second period of time is automatically adjusted to increase the frequency of the controller in said measurement mode upon controller determination of possible moisture, liquid, ice, vapor or heavy gases in accordance with said sample data in order to verify the presence of moisture, liquid, ice, vapor or heavy gases on said surface.