PIR motion sensor
First Claim
1. A passive infrared (IR) motion sensor, comprising:
- at least a first IR detector outputting a first signal having a first frequency in response to a stimulus in a detection volume of the first detector;
at least a second IR detector outputting a second signal, the second signal having a second frequency different than the first frequency when the stimulus is a moving object, the second signal having the first frequency when the stimulus is non-moving; and
a processing system receiving the first and second signals and at least partially based on the first and second signals having different frequencies, outputting a detection signal representative of the moving object, and otherwise, when both detectors output the same frequency, not outputting a signal representative of a moving object.
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Accused Products
Abstract
A passive infrared sensor uses two detectors having elements of different configurations such that each element outputs a respective frequency when an object moves in front of it. Based on the presence of two frequencies with similar peak and/or slope characteristics, a motion signal is output to, e.g., activate an alarm. In another embodiment the detectors have plural elements with the elements of one detector being wired in a dimension that is orthogonal to the dimension in which the elements of the other detector are wired. The signals from the detectors are combined to determine motion and size of object. The detector elements can also be configured differently from each other as in the first embodiment, and the polarities of signals can be used to determine direction of motion.
27 Citations
22 Claims
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1. A passive infrared (IR) motion sensor, comprising:
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at least a first IR detector outputting a first signal having a first frequency in response to a stimulus in a detection volume of the first detector; at least a second IR detector outputting a second signal, the second signal having a second frequency different than the first frequency when the stimulus is a moving object, the second signal having the first frequency when the stimulus is non-moving; and a processing system receiving the first and second signals and at least partially based on the first and second signals having different frequencies, outputting a detection signal representative of the moving object, and otherwise, when both detectors output the same frequency, not outputting a signal representative of a moving object. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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- 8. A processing system connected to first and second PIR detectors for outputting a detect signal only if signals received from both detectors have different frequencies from each other, the detect signal not being output if the signals from both detectors have the same frequency as each other.
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11. A PIR sensor, comprising:
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at least a first detector configured for outputting signals representative of at least one of at least two points along a first dimension defined by the first detector, the first detector receiving IR radiation from a first monitored sub-volume of space; and at least a second detector configured for outputting signals representative of at least one of at least two points along a second dimension defined by the second detector, the second dimension being different from the first dimension, the second detector receiving IR radiation from a second monitored sub-volume of space that at least partially overlaps the first monitored sub-volume of space, wherein a moving object is indicated when the signals from the first detector have a different frequency than the signals from the second detector and a non-moving stimulus is indicated when the signals from the first detector have the same frequency as the signals from the second detector. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A system for discriminating a moving object in a monitored space from a non-moving object characterized by non-constant radiation, comprising:
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means for receiving a first frequency from a first passive IR detector; means for receiving a second frequency from a second passive IR detector, the first and second frequencies not being equal in the presence of the moving object and being equal in the presence of the non-moving object; and means for outputting a signal indicating the presence of the moving object only if both the first and second frequencies are substantially simultaneously received and are not equal to each other, and not outputting the signal indicating the presence of the moving object if both the first and second frequencies are substantially simultaneously received and are equal to each other. - View Dependent Claims (19, 20, 21, 22)
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Specification