US 6,188,318 B1 · Dual-technology intrusion detector with pet immunity

Abstract

A dual-sensing intrusion detection device for detecting an intruder comprising a PIR sensor and a microwave sensor. The device comprises PIR processing means and microwave processing means, means for summing the processed PIR signal with the processed microwave signal to generate a summed signal, and means for comparing the summed signal to a sum threshold value to determine if an alarm condition exists. The sum threshold value is selected for optimal discrimination between a human intruder and an animal presence. An additional feature of the intrusion detection device is the generation of a PIR difference signal. This feature allows the device to compensate for the limited bandwidth of the PIR sensor and to be more sensitive to a human intruder. The processing of the sensor signals includes an integration technique that sums the amplitude values of the signal and causes the sum to decay at a slow rate. In addition, the slow decay rate causes the signal to be spread out in time, thereby allowing the signals from both detectors to be above the threshold at the same time.

Claims56

Dependent claims

A dual-sensing intrusion detection device for detecting an intruder in a volume of space comprising:

a) a Passive Infra Red sensing means for generating a detected PIR signal in response to sensing an intruder in the volume of space,
b) PIR processing means for processing the PIR signal and for generating a processed PIR signal,
c) a microwave sensing means for generating a detected microwave signal in response to sensing an intruder in the volume of space,
d) microwave processing means for processing the detected microwave signal and for generating a processed microwave signal,
e) means for generating a PIR difference signal as a function of the detected PIR signal,
f) PIR difference signal processing means for processing the difference signal and for generating a processed PIR difference signal,
g) means for summing the processed PIR signal, the processed microwave signal, and the processed PIR difference signal to generate a summed signal, and
h) means for comparing the summed signal to a sum threshold value to determine if an alarm condition exists.

5 more elements

A dual-sensing intrusion detection device for detecting an intruder in a volume of space comprising:

a) a Passive Infra Red detector for generating a detected PIR signal in response to sensing an intruder in the volume of space,
b) a microwave detector for generating a detected microwave signal in response to sensing an intruder in the volume of space,
c) a controller comprising:
i) an A/D converter for digitizing the detected PIR signal and the detected microwave signal, and
ii) a processor,
iii) memory programmed to cause the processor to execute a repetition of the steps of:
1) sampling the detected microwave signal to generate a digital microwave signal,
2) sampling the detected PIR signal to generate a current digital PIR signal,
3) subtracting a prior digitized PIR signal from the current digital PIR signal to generate a PIR difference signal,
4) summing the digital microwave signal, digital PIR signal, and the PIR difference signal to generate a summed signal, and
5) comparing the summed signal to a sum threshold to determine if an alarm condition exists.

8 more elements

A dual-sensing intrusion detection device for detecting an intruder in a volume of space comprising:

a) a passive infra red sensing means for generating a detected PIR signal in response to sensing an intruder in the volume of space,
b) PIR integration means for integrating the PIR signal and for generating a processed PIR signal, comprising:
i) A first inverting amplifier to generate an inverted PIR signal,
ii) a first diode connected to the PIR signal,
iii) a second diode connected to the inverted PIR signal, wherein the first diode and second diode have cathodes tied together to sum the PIR signal with the inverted PIR signal and to generate a summed PIR signal,
iv) a first resistor coupled to cathodes of the first and second diodes,
v) a first capacitor coupled to the first resistor wherein the first capacitor is charged by the summed PIR signal, and
vi) a second resistor coupled to the capacitor to discharge the first capacitor,
c) A microwave sensing means for generating a detected microwave signal in response to sensing an intruder in the volume of space,
d) Microwave integration means for integrating the detected microwave signal and for generating a processed microwave signal, comprising:
i) a second inverting amplifier to generate an inverted microwave signal,
ii) a third diode connected to the microwave signal,
iii) a fourth diode connected to the inverted microwave signal, wherein the third diode and fourth diode have cathodes tied together to sum the microwave signal with the inverted microwave signal and to generate a summed microwave signal,
iv) a third resistor coupled to cathodes of the third and fourth diodes,
v) a second capacitor coupled to the third resistor wherein the second capacitor is charged by the summed microwave signal, and
vi) a fourth resistor coupled to the second capacitor to discharge the second capacitor,
e) Means for summing the processed PIR signal and the processed microwave signal to generate a summed signal, and
f) Means for comparing the summed signal to a sum threshold value to determine if an alarm condition exists.

15 more elements

A dual-sensing intrusion detection device for detecting an intruder in a volume of space comprising:

a) a passive infra red sensing means for generating a detected PIR signal in response to sensing an intruder in the volume of space,
b) PIR integration means for integrating the PIR signal and for generating a processed PIR signal, comprising a microprocessor programmed to execute the steps of:
i) subtracting a first PIR sensor threshold value from the PIR signal,
ii) determining the absolute value of the PIR signal minus the first PIR sensor threshold value,
iii) comparing the absolute value of the PIR signal minus the first PIR sensor threshold value to a second PIR sensor threshold value,
iv) generating an increase in the processed PIR signal when the absolute value of the PIR signal minus the first PIR sensor threshold value is greater than the second PIR sensor threshold value,
v) generating a decrease in the processed PIR signal when the absolute value of the PIR signal minus the first PIR sensor threshold value is not greater than the second PIR sensor threshold value, and
vi) repeating steps (i)-(v).
c) A microwave sensing means for generating a detected microwave signal in response to sensing an intruder in the volume of space,
d) Microwave integration means for integrating the detected microwave signal and for generating a processed microwave signal, comprising:
i) subtracting a first microwave sensor threshold value from the microwave signal,
ii) determining the absolute value of the microwave signal minus the first microwave sensor threshold value,
iii) comparing the absolute value of the microwave signal minus the first microwave sensor threshold value to a second microwave sensor threshold value,
iv) generating an increase in the processed microwave signal when the absolute value of the microwave signal minus the first microwave sensor threshold value is greater than the second microwave sensor threshold value,
v) generating a decrease in the processed microwave signal when the absolute value of the microwave signal minus the first microwave sensor threshold value is not greater than the second microwave sensor threshold value, and
vi) repeating steps (i)-(v).
e) Means for summing the processed PIR signal and the processed microwave signal to generate a summed signal, and
f) Means for comparing the summed signal to a sum threshold value to determine if an alarm condition exists.

15 more elements

Dependencies are inferred from the claim text.

Dual-technology intrusion detector with pet immunity

Life of this patent

Dual-technology intrusion detector with pet immunity

Life of this patent

Abstract

Claims56