Method and apparatus for indicating activation of a smoke detector alarm

• US 7,015,807 B2
• Filed: 10/02/2003
• Issued: 03/21/2006
• Est. Priority Date: 10/02/2002
• Status: Active Grant

• Current Assignee: SafeAwake, LLC
• Original Assignee: Combustion Science & Engineering, Inc.
• Inventors: Roby, Richard J., Klassen, Michael S., Schemel, Christopher F., Vashishat, Diwakar, Holton, Maclain M., Flint, Kelly R.
• Primary Examiner(s): Lee, Benjamin C.
• Application Number:
  US10/676,779
• Publication Number:
  US 20040145467A1
• Time in Patent Office: 901 Days
• Field of Search: 340/531, 340/539.1, 340/539.11, 340/539.27, 340/628, 340/902, 340/407.1
• US Class Current: 340/531
• CPC Class Codes: G08B 1/08 using electric transmission ; transformation of alarm signals to electrical signals from a different medium, e.g. transmission of an electric alarm signal upon detection of an audible alarm signal
• CPC Class Codes: G08B 17/10 Actuation by presence of smoke or gases , e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
• CPC Class Codes: G08B 29/188 Data fusion; cooperative systems, e.g. voting among different detectors
• CPC Class Codes: G08B 3/10 using electric transmission; using electromagnetic transmission
• CPC Class Codes: G08B 6/00 Tactile signalling systems, e.g. personal calling systems
• CPC Class Codes: G08B 7/06 using electric transmission , e.g. involving audible and visible signalling through the use of sound and light sources
• CPC Class Codes: G09B 19/00 Teaching not covered by other main groups of this subclass teaching or practice apparatus for gun-aiming or gun-laying F41G3/26
• CPC Class Codes: G09B 21/009 Teaching or communicating with deaf persons G09B21/04 takes precedence; deaf and dumb persons G09B21/00

Abstract

A method for detecting smoke detector alarms comprises analyzing at least two parameters of ambient sound over a period of time to detect a temporal pattern of the alarm. In one embodiment, a series of samples are taken over a period of time sufficiently long to include at least one full period of a repeating sound pattern, and the two parameters are frequency and amplitude of the loudest sound in each sample. The algorithmic analysis may be triggered by a detection algorithm that utilizes a lower amount of power than the algorithmic analysis. In other embodiments, the detection apparatus is incorporated into a conventional smoke detector that will detect both smoke and an alarm from another detector. In another embodiment, a smoke detector includes a transceiver to transmit an activation signal to neighboring smoke detectors when a fire is detected and to receive an activation signal from neighboring detectors.

Claims

1. A method for detecting whether an audible alarm generated by a smoke detector is active, the audible alarm having an alarm period comprising a plurality of on periods and a plurality of off periods arranged in a predetermined temporal pattern, each of the on periods being a period during which an audible alarm sound is generated by the smoke detector, each of the off periods being a period during which no audible sound is generated by the smoke detector, the method comprising:

detecting a peak amplitude in each of a plurality of sample periods, each of the sample periods corresponding to one of the expected on or off periods in a single alarm period;

selecting a maximum peak amplitude from among the peak amplitudes;

setting an amplitude threshold, the amplitude threshold being a function of the maximum peak amplitude;

comparing each of the peak amplitudes to the amplitude threshold for each of the sample periods to determine which sample periods have a peak amplitude that exceeds the amplitude threshold;

determining whether the audible alarm is active based at least in part on whether the temporal pattern of sample periods in which the peak amplitude exceeds the amplitude threshold matches the predetermined temporal pattern.

2. The method of claim 1, further comprising the step of:

determining a frequency corresponding to the peak amplitude in each of the sample periods corresponding to an on period in the predetermined temporal pattern;

wherein the determining step is further based on whether a frequency corresponding to the peak amplitude in each of the sample periods corresponding to an on period in the predetermined temporal pattern corresponds to an alarm frequency at which each of the audible alarm sounds is generated.

3. The method of claim 1, wherein the amplitude threshold is no less than a minimum amplitude above an average ambient noise level.

4. The method of claim 1, further comprising the steps of:

obtaining, prior to the detecting step, an ambient sound sample;

examining a parameter of the ambient sound sample to determine whether the audible alarm is present; and

delaying, in the absence of a possibility that the audible alarm may be present, a period of time and repeating the obtaining and examining steps;

wherein the detecting, setting, selecting, comparing and determining steps are performed when there is a possibility that an audible alarm may be present.

5. The method of claim 1, further comprising the step of activating an alerting device when the audible alarm is active.

6. The method of claim 5, wherein the alerting device is a tactile alerting device.

7. The method of claim 1, further comprising the step of sending an activation message to a remote device.

8. A device for detecting whether an audible alarm generated by a smoke detector is active, the audible alarm having an alarm period comprising a plurality of on periods and a plurality of off periods arranged in a predetermined temporal pattern, each of the on periods being a period during which an audible alarm sound is generated by the smoke detector, each of the off periods being a period during which no audible sound is generated by the smoke detector, the device comprising:

a microphone; and

a processor connected to the microphone;

wherein the processor is configured to perform the steps of;

detecting a peak amplitude in each of a plurality of sample periods, each of the sample periods corresponding to one of the expected on or off periods in a single alarm period;

selecting a maximum peak amplitude from among the peak amplitudes;

setting an amplitude threshold, the amplitude threshold being a function of the maximum peak amplitude;

comparing each of the peak amplitudes to the amplitude threshold for each of the sample periods to determine which sample periods have a peak amplitude that exceeds the amplitude threshold;

determining whether the audible alarm is active based at least in part on whether the temporal pattern of sample periods in which the peak amplitude exceeds the amplitude threshold matches the predetermined temporal pattern.

9. The device of claim 8, wherein the processor is further configured to perform the step of:

determining a frequency corresponding to the peak amplitude in each of the sample periods corresponding to an on period in the predetermined temporal pattern;

wherein the determining step is further based on whether a frequency corresponding to the peak amplitude in each of the sample periods corresponding to an on period in the predetermined temporal pattern corresponds to an alarm frequency at which each of the audible alarm sounds is generated.

10. The device of claim 8, wherein the amplitude threshold is no less than a minimum amplitude above an average ambient noise level.

11. The device of claim 8, wherein the processor is further configured to perform the steps of:

obtaining, prior to the detecting step, an ambient sound sample;

examining a parameter of the ambient sound sample to determine whether the audible alarm is present; and

delaying, in the absence of a possibility that the audible alarm may be present, a period of time and repeating the obtaining and examining steps;

wherein the detecting, setting, selecting, comparing and determining steps are performed when there is a possibility that an audible alarm may be present.

12. The device of claim 8, further comprising an alerting device connected to the processor.

13. The device of claim 12, wherein the alerting device is a tactile alerting device.

14. The device of claim 8, wherein the processor is further configured to perform the step of sending an activation message to a remote device.