OPTICAL MOISTURE SENSOR
First Claim
1. A self-contained optical moisture sensor unit comprising:
- a housing;
a substantially planar circuit board disposed substantially horizontally in the housing;
at least one light emitter and at least one light detector mounted on the circuit board;
a lens having a predetermined geometric shape and being light transmissive, sealingly mounted on the housing, the lens comprising;
an inner sensing surface and an outer sensing surface, the outer sensing surface being substantially continuously concave in shape relative to the circuit board, and the inner sensing surface also being substantially continuously concave relative to the circuit board, and at a predetermined distance above the at least one light emitter and at least one light detector wherein the moisture sensor has a radial distance Rd which is from 68% to 80% of the radius of the outer sensing surface of the lens Rs;
at least one control circuit to control the at least one light emitter and at least one light detector; and
software to analyze at least the data received by the at least one light detector.
2 Assignments
0 Petitions
Accused Products
Abstract
A moisture sensor is provided that simultaneously achieves ruggedness, sensitivity, wide dynamic range, versatility of application, and low cost. The outer, top service of the sensor is a lens having a predetermined geometric shape which preferably makes the rain sensor resistant to the build up of debris on the outer surface as well as being effectively self-cleaning. Within a housing of the rain sensor, at least one light emitter and at least one light detector are each deployed on a substantially planar circuit board facing such outer lens surface. So arranged, light rays from the at least one emitter strike the outer lens surface and is reflected about 90°, whereupon it strikes the outer lens surface once more and is again reflected therefrom about 90° to focus back onto the at least one detector. Raindrops present on the outside surface of the sensor affect the intensity of the light rays reflected and signals from the at least one light detector are sent to control circuitry within the rain sensor. A microprocessor in the sensor processes the resulting data to detect rain intensity over a wide range so as to be capable of being effectively deployed for applications such as to emulate a tipping bucket style rain detector, providing condensation sensing, and automatically adjusting the strength of the light rays emitted by the at least one light emitter to provide improved consistency of operation of the sensor over time.
22 Citations
27 Claims
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1. A self-contained optical moisture sensor unit comprising:
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a housing; a substantially planar circuit board disposed substantially horizontally in the housing; at least one light emitter and at least one light detector mounted on the circuit board; a lens having a predetermined geometric shape and being light transmissive, sealingly mounted on the housing, the lens comprising; an inner sensing surface and an outer sensing surface, the outer sensing surface being substantially continuously concave in shape relative to the circuit board, and the inner sensing surface also being substantially continuously concave relative to the circuit board, and at a predetermined distance above the at least one light emitter and at least one light detector wherein the moisture sensor has a radial distance Rd which is from 68% to 80% of the radius of the outer sensing surface of the lens Rs;
at least one control circuit to control the at least one light emitter and at least one light detector; andsoftware to analyze at least the data received by the at least one light detector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A self-contained optical moisture sensor unit comprising:
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a housing; a substantially planar circuit board disposed substantially horizontally in the housing; at least one light emitter and at least one light detector mounted on the circuit board; a lens having a predetermined geometric shape and being light transmissive, sealingly mounted on the housing, the lens comprising; an inner sensing surface and an outer sensing surface, the outer sensing surface being substantially continuously concave in shape relative to the circuit board, and the inner sensing surface having a center portion being substantially continuously concave relative to the circuit board, and a peripheral planar portion proximate and at a predetermined distance above the at least one light emitter and at least one light detector wherein the moisture sensor has a radial distance Rd which is from 68% to 80% of the radius of the outer sensing surface of the lens Rs;
at least one control circuit comprising at least one microprocessor to control the at least one light emitter and at least one light detector; andsoftware to analyze at least the data received by the at least one light detector. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method of measuring moisture with an optical moisture sensor comprising:
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providing a substantially planar circuit board to which is mounted at least one light emitter and at least one light detector; activating the at least one light emitter and at least one light detector via at least one control circuit; emitting a light beam comprising a plurality of light rays from the at least one emitter through a highly light transmissive lens having a predetermined, geometric shape, an outer sensing surface of the lens substantially conforming to the geometric shape of the lens and an inner sensing surface of the lens having a shape substantially conforming to the lens shape, whereby the light rays are reflected by an emitter sensing area of the outer sensing surface at an angle of about 90°
through the lens to contact a detector sensing area of the outer sensing surface, where they are reflected at an angle of about 90°
through the lens and are received by the at least one light detector;sensing the intensity of the light rays received by the at least one light detector; and determining if the transmission efficiency of the optical path of the light rays is diminished to indicate that at least one drop of moisture is present on the emitter sensing area, the detector sensing area, or both.
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22. A method of measuring moisture with an optical moisture sensor comprising:
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providing a substantially planar circuit board to which is mounted at least one light emitter and at least one light detector; activating the at least one light emitter and at least one light detector via at least one control circuit; emitting a light beam comprising a plurality of light rays from the at least one emitter through a highly light transmissive lens having a predetermined, geometric shape, an outer sensing surface of the lens substantially conforming to the geometric shape of the lens and an inner sensing surface of the lens having a compound shape comprising a center portion substantially conforming to the lens shape and generally planar peripheral areas proximate and above the at least one emitter and at least one detector, whereby the light rays are reflected by an emitter sensing area of the outer sensing surface at an angle of about 90°
through the lens to contact a detector sensing area of the outer sensing surface, where they are reflected at an angle of about 90°
through the lens and are received by the at least one light detector;sensing the intensity of the light rays received by the at least one light detector; and determining if the transmission efficiency of the optical path of the light rays is diminished to indicate that at least one drop of moisture is present on the emitter sensing area, the detector sensing area, or both. - View Dependent Claims (23, 24, 25, 26, 27)
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Specification