Motion detector with improved signal discrimination
AssigneeIntelectron Products Company
InventorsWade P. Lee, Scott T. Evans
Life of this patent
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Abstract
An infrared motion detection device for detecting the presence of a target object including special circuitry for reducing false alarms. In particular, coupling circuitry is interposed between signal processing circuitry and comparator circuitry, which serves to match the baseline level of the signal from the signal processing circuitry with the baseline level of a threshold or thresholds defined by the comparator circuitry. The coupling circuitry may be implemented in a particularly simple manner, which reduces the manufacturing cost of the circuitry and the device.
Claims10
In an infrared motion detection device for detecting the presence of a target object, said device including at least one infrared detector providing an electrical signal responsive to infrared radiation incident thereon, filter circuitry for processing said electrical signal, said filter circuitry receiving said electrical signal and providing a derivative signal representative of said incident infrared radiation, and comparator circuitry defining a threshold, said comparator circuitry receiving said derivative signal and providing an output signal in response thereto only when said derivative signal exceeds said threshold, said output signal being used to trigger a signal for energizing a light or alarm in response to the presence of said target object, the improvement comprising:
- coupling means coupling said filter circuitry with said comparator circuitry for matching the baseline level of said derivative signal with the baseline level of said comparator threshold.
In an infrared motion detection device for detecting the presence of a target object, said device including a pair of detectors, each providing an electrical signal responsive to infrared radiation incident thereon, filter circuitry for processing the electrical signals from said detectors and providing a derivative signal representative of said incident infrared radiation, said filter circuitry having a steady state output level, and window comparator circuitry defining a threshold window, said window comparator circuitry receiving said derivative signal and providing an output signal in response thereto only when said derivative signal falls outside the bounds of said threshold window, said output signal being used to trigger a signal for energizing a light or alarm in response to the presence of said target object, the improvement comprising:
- window centering means coupling said filter circuitry with said window comparator circuitry for centering said threshold window with respect to the steady state output level of said filter circuitry.
Dependencies are inferred from the claim text.