Passive infrared sensor self test with known heat source

• US 10,012,548 B2
• Filed: 11/05/2015
• Issued: 07/03/2018
• Est. Priority Date: 11/05/2015
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google LLC (Alphabet Inc.)
• Inventors: Witty, Evan, Dai, Andrew
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): Faye, Mamadou
• Application Number:
  US14/933,088
• Publication Number:
  US 20170131149A1
• Time in Patent Office: 971 Days
• CPC Class Codes: G01J 5/026 Control of working procedures of a pyrometer, other than calibration; Bandwidth calculation; Gain control
• CPC Class Codes: G01J 5/0896 using a light source, e.g. for illuminating a surface
• CPC Class Codes: G01J 5/34 using capacitors, e.g. pyroelectric capacitors
• CPC Class Codes: G01J 5/53 Reference sources, e.g. standard lamps; Black bodies
• CPC Class Codes: G01J 5/80 Calibration using comparison with reference sources G01J5/52

Abstract

A passive infrared sensor having a radiation capture component may be housed within a sensor device. The device may also house radiation emission components, such as light emitting diodes, in proximity to the capture component. Electronic circuitry within the device may generate a signal that causes the emission components to emit radiation that includes wavelengths in the infrared spectrum. The infrared radiation may be captured at the capture component. Characteristics of a signal generated by the capture component may be compared to test characteristics. Based on this comparison, it may be determined that the passive infrared sensor is not operating properly.

Claims

1. A method comprising:

receiving a signal from a sensor indicating that a device is not mounted properly;

emitting radiation from an emission component arranged in a single housing of the device in response to the signal;

capturing infrared radiation at a capture component arranged in the single housing of the device;

comparing a characteristic of the captured infrared radiation to a test characteristic; and

determining the capture component is not operating properly when the characteristic of the captured infrared radiation differs from the test characteristic by greater than a threshold quantity.

2. The method of claim 1, wherein the emitted radiation comprises infrared radiation having energy that is greater than energy of infrared radiation emitted from a background source.

3. The method of claim 1, wherein the emitted radiation comprises infrared radiation having energy that is less than energy of infrared radiation emitted from an average human at a distance of approximately 6 meters from the capture component.

4. The method of claim 1, wherein the emitted radiation comprises radiation having a wavelength of approximately 8-14 microns.

5. The method of claim 1, wherein the captured infrared radiation comprises at least a portion of the emitted radiation.

6. The method of claim 1, wherein:

the test characteristic comprises a test voltage generated at the capture component when radiation having energy substantially equal to energy of the emitted radiation is emitted from the emission component and captured at the capture component,

the characteristic of the captured infrared radiation comprises a voltage generated at the capture component when the captured infrared radiation is captured at the capture component, and

comparing comprises determining a difference between the test voltage and the voltage generated at the capture component when the captured infrared radiation is captured.

7. The method of claim 1, further comprising, in response to determining the capture component is not operating properly, providing to a component of a home automation system, a status of the device that indicates the device is not operating properly.

8. The method of claim 1, further comprising:

prior to emitting the radiation, detecting an event by a sensor that is remote from the device and that is in communication with the device; and

providing a request to the device to determine a status of the device,

wherein emitting the radiation is in response to receiving the request at the device.

9. The method of claim 1, further comprising:

prior to emitting the radiation, detecting an event by a sensor that is remote from the device and that is in communication with the device;

determining a period of time has elapsed after detecting the event;

determining an event has not been detected by the device within the period of time; and

providing a request to the device to determine a status of the device,

wherein emitting the radiation is in response to receiving the request at the device.

10. A system comprising:

a device comprising a radiation emission component arranged in a single housing of the device and a radiation capture component arranged in the single housing of the device; and

a processor in communication with the device and configured to execute instructions comprising;

receiving a signal from a sensor indicating that the device is not mounted properly;

emitting radiation from the emission component in response to the signal;

capturing infrared radiation at the capture component;

comparing a characteristic of the captured infrared radiation to a test characteristic;

determining the capture component is not operating properly when the characteristic of the captured infrared radiation differs from the test characteristic by greater than a threshold quantity; and

determining a status of the device based on determining the capture component is not operating properly.

11. The system of claim 10, wherein the emission component comprises a light emitting diode.

12. The system of claim 10, wherein the capture component comprises a pyroelectric material.

13. A system of claim 10, wherein the emission component is disposed on the device substantially adjacent to the capture component.

14. The system of claim 10, wherein the device further comprises an attachment sensor that detects when the device is not properly mounted.

15. The system of claim 10, wherein the device further comprises an attachment sensor that detects when the device is not properly mounted, and the attachment sensor comprises at least one selected from the group consisting of:

a mechanical switch that provides an electrical signal when the mechanical tamper switch has been triggered;

an electrical switch comprising a first electrode housed in an attachment component of the device and a second electrode disposed on a surface to which the device is mounted;

an accelerometer;

a magnetic switch; and

a light sensor.

16. The system of claim 10, wherein the instructions further comprise:

prior to emitting the radiation, detecting an event by a sensor that is remote from the device and that is in communication with the processor; and

providing a request to the device to determine a status of the device,

wherein emitting the radiation is in response to receiving the request at the device.

17. The system of claim 10, wherein the instructions further comprise:

prior to emitting the radiation, detecting an event by a sensor that is remote from the device and that is in communication with the processor;

determining a period of time has elapsed after detecting the event;

determining an event has not been detected by the device within the period of time; and

providing a request to the device to determine a status of the device,

wherein emitting the radiation is in response to receiving the request at the device.

18. A non-transitory computer readable medium storing instructions comprising:

detecting a device is not properly mounted;

in response to detecting the device is not properly mounted, emitting radiation from an emission component arranged in a single housing of the device;

capturing infrared radiation at a capture component arranged in the single housing of the device;

comparing a characteristic of the captured infrared radiation to a test characteristic; and

determining the capture component is not operating properly when the characteristic of the captured infrared radiation differs from the test characteristic by greater than a threshold quantity.

19. The non-transitory computer readable medium of claim 18, wherein detecting the device is not properly mounted comprises at least one selected from the group consisting of:

determining a signal associated with proper mounting of the device is no longer present,

determining a signal associated with improper mounting of the device is present,

determining an accelerometer sensor value exceeds a threshold value, and

determining a light sensor value exceeds a threshold value.

20. The non-transitory computer readable medium of claim 18, wherein:

the test characteristic comprises a test sequence of voltage peaks generated at the capture component when radiation having energy substantially equal to energy of the emitted radiation is emitted from the emission component and captured at the capture component,

the characteristic of the captured infrared radiation comprises a sequence of voltage peaks generated at the capture component when the captured infrared radiation is captured at the capture component, and

comparing comprises determining a difference between the test sequence of voltage peaks and the sequence of voltage peaks generated at the capture component when the captured infrared radiation is captured.