Dual sensor intruder alarm
First Claim
1. A dual sensor intruder alarm (DSIA) for detecting an intruder in a security zone monitored by the DSIA comprising:
- a PIR sensor;
an additional sensor;
a controller that determines an operating difference between the ambient temperature and a normative surface temperature of an intruder in the security zone; and
wherein if the operating difference is equal to or greater than a predetermined threshold difference, the controller operates in a dual trigger mode and determines whether an intruder is present in the security zone using signals from both the PIR sensor and the additional sensor and if the operating difference is less than the predetermined threshold difference, the controller operates in a single trigger mode and uses signals from the additional sensor but not from the PIR sensor to determine presence of an intruder.
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Accused Products
Abstract
A dual sensor intruder alarm (DSIA) for detecting an intruder in a security zone monitored by the DSIA comprising: a PIR sensor; an additional sensor, and a controller that determines an operating difference between the ambient temperature and a normative surface temperature of an intruder in the security zone; wherein if the operating difference is equal to or greater than a predetermined threshold difference, the controller determines whether an intruder is present in the security zone using signals from both the PIR sensor and the additional sensor and if the operating difference is less than the predetermined threshold difference, the controller uses signals from the additional sensor but not from the PIR sensor to determine presence of an intruder.
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Citations
14 Claims
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1. A dual sensor intruder alarm (DSIA) for detecting an intruder in a security zone monitored by the DSIA comprising:
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a PIR sensor;
an additional sensor;
a controller that determines an operating difference between the ambient temperature and a normative surface temperature of an intruder in the security zone; and
wherein if the operating difference is equal to or greater than a predetermined threshold difference, the controller operates in a dual trigger mode and determines whether an intruder is present in the security zone using signals from both the PIR sensor and the additional sensor and if the operating difference is less than the predetermined threshold difference, the controller operates in a single trigger mode and uses signals from the additional sensor but not from the PIR sensor to determine presence of an intruder. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for determining presence of an intruder in a security zone, the method comprising:
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monitoring the zone using a PIR sensor and an additional sensor that generate signals responsive to presence of an intruder in the zone;
determining an ambient temperature for the security zone;
determining an operating temperature difference between the ambient temperature and a normative surface temperature for an intruder in the zone;
using signals from both the PIR and additional sensors to determine presence of an intruder in the zone if the operating difference is greater than or equal to a predetermined threshold temperature difference; and
using signals from the additional sensor but not the PIR sensor to determine presence of an intruder in the zone if the operating difference is less than the threshold temperature difference. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification