SYSTEM AND METHOD FOR HIGH-SENSITIVITY SENSOR

• US 20150011169A1
• Filed: 09/22/2014
• Published: 01/08/2015
• 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 9,019,110 B2
• Time in Patent Office: Days
• US Class Current: 455/73
• 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 device, comprising:

a housing;

a smoke chamber arranged within the housing and configured to receive air from outside of the housing of the device;

an emitter arranged within the housing and configured to emit electromagnetic radiation into the smoke chamber;

a sensor arranged within the housing and configured to measure a scattered portion of the electromagnetic radiation emitted by the emitter into the smoke chamber, the measurement of the scattered portion of the electromagnetic radiation being dependent on an ambient temperature of the device, the ambient temperature being a temperature within the housing of the device;

a temperature sensor arranged within the housing and configured to measure the ambient temperature of the device; and

a temperature compensation element configured to correct a measurement measured by the sensor based on the ambient temperature measured by the temperature sensor, said correcting at least partially offsetting a change in the measurement measured by the sensor caused by a change in the ambient temperature of the device.

2. The device of claim 1, wherein the temperature sensor is part of the temperature compensation element, the temperature compensation element receives an analog signal output by the sensor, and the temperature compensation element transmits a corrected analog signal to a controller.

3. The device of claim 2, wherein the temperature sensor is located within the housing and outside of the smoke chamber.

4. The device of claim 2, wherein the temperature compensation element comprises an amplifier that receives the analog signal output by the sensor, wherein the measured ambient temperature made by the temperature sensor is used in determining an amount of gain of the amplifier.

5. The device of claim 1, wherein the temperature compensation element is a controller that receives the measured ambient temperature and is configured to compute a correction value used in correcting the measurement made by the sensor.

6. The device of claim 5, wherein the temperature sensor is located within the smoke chamber and the temperature sensor transmits the measured ambient temperature to the controller.

7. The device of claim 1, further comprising:

a second temperature sensor located within the smoke chamber, wherein the temperature sensor is located within the sensor device but outside of the smoke chamber.

8. The device of claim 1, further comprising:

a transceiver arranged within the housing for wireless communication; and

a controller arranged within the housing, configured to;

cause the sensor device to measure the scattered portion of the electromagnetic radiation emitted by the emitter into the smoke chamber while in a low-power mode; and

exit the low power mode and enter an awake mode based on a measurement measured by the sensor being indicative of an anomalous condition being present, wherein wireless communication via the wireless transceiver occurs only when the sensor unit is out of the low-power mode.

9. The device of claim 8, wherein the transceiver is configured to listen for one or more instructions while operating in the awake mode, and, in response to receiving the one or more instructions, the controller is configured to perform one or more functions requested by the one or more instructions while operating in the awake mode.

10. The device of claim 8, wherein the device is configured to:

measure signal strengths of wireless signals received by the transceiver from one or more wireless devices; and

wirelessly communicate a first message indicative of the signal strengths to another device.

11. A method for adjusting sensor measurements, the method comprising:

emitting electromagnetic radiation into a smoke chamber, the smoke chamber configured to receive air;

measuring a scattered portion of the electromagnetic radiation in the smoke chamber, the measurement of the scattered portion of the electromagnetic radiation being dependent on an ambient temperature;

measuring the ambient temperature of the sensor device; and

correcting a measurement of the scattered portion of the electromagnetic radiation in the smoke chamber based on the measured ambient temperature.

12. The method for adjusting sensor measurements of claim 11, wherein correcting the measurement of the scattered portion of the electromagnetic radiation comprises:

amplifying a signal corresponding to the measurement of the scattered portion of the electromagnetic radiation, wherein a gain level for amplifying the signal is based on the measured ambient temperature of the sensor device.

13. The method for adjusting sensor measurements of claim 11, wherein the measurement of the ambient temperature is performed outside of the smoke chamber.

14. The method for adjusting sensor measurements of claim 13, further comprising:

measuring a second ambient temperature within the smoke chamber, wherein correcting the measurement of the scattered portion of the electromagnetic radiation comprises correcting the measurement of the scattered portion of the electromagnetic radiation based on the ambient temperature and the second ambient temperature.

15. The method for adjusting sensor measurements of claim 13, further comprising:

calculating a temperature correction value using the ambient temperature and the second ambient temperature.

16. The method for adjusting sensor measurements of claim 13, further comprising:

measuring a second portion of electromagnetic radiation in the smoke chamber, wherein electromagnetic radiation is not emitted by an emitter within the smoke chamber when the second portion is measured.

17. The method for adjusting sensor measurements of claim 13, further comprising:

measuring signal strengths of wireless signals received by the transceiver from one or more wireless devices; and

wirelessly communicating one or more messages indicative of the measured signal strengths to another device.

18. A system, comprising:

means for emitting electromagnetic radiation into a smoke chamber, the smoke chamber configured to receive air;

means for measuring a scattered portion of the electromagnetic radiation in the smoke chamber, the measurement of the scattered portion of the electromagnetic radiation being dependent on an ambient temperature;

means for measuring the ambient temperature of the system; and

means for correcting a measurement of the scattered portion of the electromagnetic radiation based on the measured ambient temperature to at least partially offset a change in the measurement caused by the ambient temperature.

19. The system of claim 18, further comprising:

means for measuring signal strengths of wireless signals received by the transceiver from one or more wireless devices; and

means for wirelessly communicating one or more messages indicative of the measured signal strengths to another device.

20. The system of claim 19, wherein the means for wirelessly communicating uses a spread spectrum technique.