Infrared detector for detecting motion and fire and an alarm system including the same
First Claim
1. A detector which detects motion and changes in ambient temperature comprising:
- a) a first passive infrared sensor and a second passive sensor, said first and second passive sensors coupled to each other in phase opposition and providing a first output;
b) first circuit means coupled to said first output for providing an intrusion alarm when infrared radiation detected by said first passive infrared detector differs from said second passive infrared detector according to first criteria; and
c) second circuit means coupled to said first passive infrared sensor at a common connection between said first and second passive infrared sensors for providing an ambient temperature change alarm when said first passive infrared sensor detects a change in infrared radiation that exceeds a predetermined amount over a predetermined time.
0 Assignments
0 Petitions
Accused Products
Abstract
A integrated IR detector for detecting both motion and fire/smoke includes in one embodiment a single source of IR radiation and separate IR sensors for sensing motion and smoke. The separate sensors are coupled by their outputs to separate amplifier circuits and provide separate outputs indicating motion (intrusion) detection and smoke detection. The entire arrangement of IR source and dual sensors are mounted in a single housing and powered by a common power supply. In a second embodiment, a single passive IR motion detector having a pair of phase opposed series connected sensors is coupled to a circuit for detecting motion (intrusion) while one of the pair of sensors is coupled to a circuit for sensing changes in ambient temperature. The circuit for detecting ambient temperature changes includes logic analysis and time constant filtering to produce an alarm signal only when ambient temperature changes exceed a preset threshold rate of degrees per second. Common power supplies and control units are disclosed which allow coupling alarm signals on a single two-wire or four-wire circuit.
-
Citations
7 Claims
-
1. A detector which detects motion and changes in ambient temperature comprising:
-
a) a first passive infrared sensor and a second passive sensor, said first and second passive sensors coupled to each other in phase opposition and providing a first output; b) first circuit means coupled to said first output for providing an intrusion alarm when infrared radiation detected by said first passive infrared detector differs from said second passive infrared detector according to first criteria; and c) second circuit means coupled to said first passive infrared sensor at a common connection between said first and second passive infrared sensors for providing an ambient temperature change alarm when said first passive infrared sensor detects a change in infrared radiation that exceeds a predetermined amount over a predetermined time. - View Dependent Claims (2, 3, 4, 5)
-
-
6. An alarm system comprising:
-
a) an infrared detector for detecting both fire and motion, said infrared detector comprising, 1) a first passive infrared sensor and a second passive sensor, said first and second passive sensors coupled to each other in phase opposition and providing a first output, 2) first circuit means coupled to said first output for providing an intrusion alarm signal when infrared radiation detected by said first passive infrared detector differs from said second passive infrared detector according to first criteria, and 3) second circuit means coupled to said first passive infrared sensor at a common connection between said first and second passive infrared sensors for providing a fire alarm signal when said first passive infrared sensor detects a change in infrared radiation that exceeds a predetermined amount over a predetermined time; b) power supply means for supplying power to said infrared detector; and c) control unit means for receiving said intrusion alarm signal and said fire alarm signal. - View Dependent Claims (7)
-
Specification