SYSTEM AND METHOD FOR HIGH-SENSITIVITY SENSOR

• US 20100271217A1
• Filed: 11/24/2009
• Published: 10/28/2010
• Est. Priority Date: 05/27/2004
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Kates, Lawrence
• Granted Patent: US 8,638,215 B2
• Time in Patent Office: Days
• US Class Current: 340/604
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 2110/50 Air quality properties
• CPC Class Codes: F24F 7/007 with forced flow using ducting systems F24F7/06
• CPC Class Codes: G01N 33/0006 Calibrating gas analysers
• CPC Class Codes: G01N 33/0065 using more than one threshold
• CPC Class Codes: G01N 33/0075 for multiple spatially distributed sensors, e.g. for environmental monitoring transmission systems for measured values G08C
• 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 17/107 for detecting light-scattering due to smoke
• CPC Class Codes: G08B 17/11 using an ionisation chamber for detecting smoke or gas
• CPC Class Codes: G08B 19/00 Alarms responsive to two or more different undesired or abnormal conditions, e.g. burglary and fire, abnormal temperature and abnormal rate of flow
• CPC Class Codes: G08B 21/182 Level alarms, e.g. alarms responsive to variables exceeding a threshold
• CPC Class Codes: G08B 25/007 Details of data content structure of message packets; data protocols
• CPC Class Codes: G08B 25/009 Signalling of the alarm condition to a substation whose identity is signalled to a central station, e.g. relaying alarm signals in order to extend communication range
• CPC Class Codes: G08B 25/10 using wireless transmission systems G08B25/009 takes precedence
• CPC Class Codes: G08B 27/005 with transmission via computer network
• CPC Class Codes: G08B 29/26 by updating and storing reference thresholds
• CPC Class Codes: H04B 1/401 for selecting or indicating operating mode
• CPC Class Codes: H04B 1/69 Spread spectrum techniques

Abstract

A sensor unit that includes at least one sensor configured to measure an ambient condition is described. The controller can be configured to receive instructions, to report a notice level when the controller determines that data measured by the at least one sensor fails a report threshold test corresponding to a report threshold value. The controller can also be configured to obtain a plurality of calibration measurements from the at least one sensor during a calibration period and to adjust the threshold based on the calibration measurements. The controller can be configured to compute a first threshold level corresponding to background noise and a second threshold level corresponding to sensor noise, and to compute the report threshold value from the second threshold. In one embodiment, the sensor unit adjusts one or more of the thresholds based on ambient temperature.

Claims

1. A sensor unit, comprising:

at least one sensor configured to measure an ambient condition;

a controller, said controller configured to operate said at least one sensor to obtain measurement data related to said ambient condition, said controller configured to compute an alert level at least in part from said measurement data, said controller configured to report at least a portion of said measurement data when said alert level exceeds a threshold; and

a fan provided to said controller, said fan configured to improve ambient air exchange with said at least one sensor, said controller configured to operate said fan in connection with said at least one sensor to improve a responsiveness of said at least one sensor to changes in said ambient conditions.

2. The sensor unit of claim 1, wherein said at least one sensor comprises a smoke sensor.

3. The sensor unit of claim 1, said controller configured to receive said threshold from a central control system.

4. The sensor unit of claim 1, said controller configured to receive said threshold from an external source.

5. The sensor unit of claim 1, wherein said at least one sensor comprises a scattering smoke sensor.

6. The sensor unit of claim 1, wherein said at least one sensor comprises a moisture sensor.

7. The sensor unit of claim 1, wherein said at least one sensor comprises a humidity sensor.

8. The sensor unit of claim 1, wherein said at least one sensor comprises a carbon monoxide sensor.

9. The sensor unit of claim 1, wherein said at least one sensor comprises a flammable gas sensor.

10. The sensor unit of claim 1, wherein said alert level is computed, at least in part, as an average of a plurality of sensor data values.

11. The sensor unit of claim 1, wherein said alert level is computed, at least in part, as a weighted average of a plurality of sensor data values.

12. The sensor unit of claim 1, wherein said alert level is computed according to how far a sensor reading has risen above a report threshold value.

13. The sensor unit of claim 1, wherein said alert level is computed as a function of how far and how rapidly sensor readings have risen above a threshold value.

14. The sensor unit of claim 1, wherein said alert level is computed as a function of how many sensor readings have been measured above said threshold value.

15. The sensor unit of claim 1, wherein said alert level is computed as a function of what percentage of recent sensor readings have been measured above a threshold value.

16. The sensor unit of claim 1, wherein a threshold value of an optical smoke sensor is computed using, at least in part, temperature information from a temperature sensor.

17. The sensor unit of claim 1, wherein said controller is configured to operate said fan prior to one or more measurement periods.

18. The sensor unit of claim 1, wherein said controller is configured to operate said fan in response to one or more commands from a central control system.

19. The sensor unit of claim 1, wherein said controller is configured to operate said fan in response to one or more commands from a monitoring system that monitors a plurality of sensor units.

20. The sensor unit of claim 1, wherein said controller is configured to operate said fan in response to one or more commands from a monitoring system that monitors a plurality of sensor units, said monitoring system configured to send said one or more commands in response to smoke detection by a second sensor unit.

21. The sensor unit of claim 1 said at least one sensor further comprising a calibration module configured to provide calibration data.

22. The sensor unit of claim 1 said at least one sensor further comprising a calibration module configured to provide software for use by said controller.