SYSTEMS AND METHODS FOR SENSING ENVIRONMENTAL CHANGES USING LIGHT SOURCES AS SENSORS

• US 20140375352A1
• Filed: 09/14/2012
• Published: 12/25/2014
• Est. Priority Date: 09/15/2011
• Status: Active Grant

• Current Assignee: University of Washington
• Original Assignee: University of Washington
• Inventors: Patel, Shwetak N., Gupta, Sidhant, Reynolds, Matthew S.
• Granted Patent: US 9,618,553 B2
• Time in Patent Office: Days
• US Class Current: 324/764.01
• CPC Class Codes: G01R 29/0814 Field measurements related to measuring influence on or from apparatus, components or humans EMC, EMI and similar testing in general G01R31/001, e.g. in ESD, EMI, EMC, EMP testing, measuring radiation leakage; detecting presence of micro- or radiowave emitters; dosimetry; testing shielding; measurements related to lightning
• CPC Class Codes: G01R 29/0885 using optical probes, e.g. electro-optical, luminescent, glow discharge, or optical interferometers
• CPC Class Codes: G01R 31/001 Measuring interference from external sources to, or emission from, the device under test, e.g. EMC, EMI, EMP or ESD testing measuring electromagnetic fields G01R29/08; circuits for generating HV pulses in dielectric strength testing G01R31/14
• CPC Class Codes: G01R 31/086 in power transmission or distribution networks, i.e. with interconnected conductors

Abstract

Systems and methods for sensing environmental changes using electromagnetic interference (EMI) signals are disclosed herein. An EMI monitoring system may be used to monitor an EMI signal of one or more light sources provided over a power line, e.g., in a home or building. The received EMI energy at the power line may be analyzed to detect variations in the EMI signature indicative of environmental changes occurring in the proximity of the light sources. Environmental changes that may be sensed include, but are not limited to, proximity, touch, motion, and temperature change.

Claims

1. A method comprising:

illuminating a space with a light source, wherein the light source includes an internal oscillator used during the illuminating; and

sensing an environmental change with the light source based, at least in part, on a change in operation of the internal oscillator.

2. The method of claim 1, further comprising:

receiving an electromagnetic interference signal from the light source;

sampling the electromagnetic interference signal to generate a set of environmental data; and

analyzing the set of environmental data to identify the environmental change.

3. The method of claim 2, wherein the light source comprises a bulb having a ballast, a switching power supply, or a combination thereof.

4. The method of claim 3, wherein analyzing the set of environmental data comprises:

determining whether the environmental change comprises motion relative to the bulb, a touch of the bulb, a hover near the bulb, a touch of a lamp of the bulb, a temperature variation, or a combination thereof.

5. The method of claim 2, wherein receiving the electromagnetic interference signal comprises:

receiving the electromagnetic interference signal over a power network.

6. The method of claim 2, wherein receiving the electromagnetic interference signal comprises:

receiving the electromagnetic interference signal within the light source.

7. The method of claim 2, wherein analyzing the set of environmental data comprises:

identifying variations in a fundamental frequency of the electromagnetic interference signal.

8. An electromagnetic interference monitoring system comprising:

a power network interface configured to receive an electromagnetic interference signal over a power network from a light source operating in accordance with an oscillator signal; and

at least one processing unit and at least one computer readable medium encoded with instructions that, when executed, cause the at least one processing unit to;

process the electromagnetic interference signal; and

sense an environmental change based on a variation in the processed electromagnetic interference signal according to one or more criteria, wherein the environmental change caused the variation in the electromagnetic interference signal.

9. The electromagnetic interference monitoring system of claim 8, wherein the power network interface is configured to receive the electromagnetic interference signal over a power network using inductive coupling.

10. The electromagnetic interference monitoring system of claim 8, wherein the electromagnetic interference signal comprises a fundamental frequency and a plurality of harmonic frequencies.

11. The electromagnetic interference monitoring system of claim 8, wherein the light source comprises a bulb having a ballast, a bulb having a switching power supply, or a combination thereof.

12. The electromagnetic interference monitoring system of claim 8, wherein the system further includes a transform component configured to convert the electromagnetic interference signal to the frequency domain;

a frequency detector component configured to identify one or more frequencies of the electromagnetic interference signal and sum the one or more frequencies of the electromagnetic interference signal over time; and

a filter configured to smooth the summed electromagnetic interference signal.

13. The electromagnetic interference monitoring system of claim 8, wherein the environmental change comprises a gesture, a temperature variation, or a combination thereof.

14. The electromagnetic interference monitoring system of claim 13, wherein the gesture comprises motion relative to the light source, a touch of the light source, a hover near the light source, a touch of the light source housing, or a combination thereof.

15. The electromagnetic interference monitoring system of claim 8, wherein the one or more criteria includes criteria for rates of change and magnitude.

16. The electromagnetic interference monitoring system of claim 8, wherein the instructions further cause the at least one processing unit to:

monitor a frequency range comprising a fundamental frequency of the electromagnetic interference signal.

17. A method, comprising:

monitoring a plurality of frequency ranges on a power network;

receiving an electromagnetic interference signal having a fundamental frequency within one of the plurality of frequency ranges;

processing the electromagnetic interference signal; and

after processing the electromagnetic interference signal, sensing environmental changes based, at least in part, on one or more variations of the electromagnetic interference signal.

18. The method of claim 17, wherein monitoring the plurality of frequency ranges comprises:

rejecting a power signal on the power network.

19. The method of claim 17, wherein each of the plurality of frequency ranges corresponds to a respective light source.

20. The method of claim 19, wherein one of the respective light sources comprises a bulb having a ballast, a switching power supply, or a combination thereof.

21. The method of claim 17, further comprising:

calibrating with a light source; and

responsive to the calibrating, monitoring the one of the plurality of frequency ranges.

22. The method of claim 21, wherein calibrating with the light source comprises:

detecting a presence of the electromagnetic interference signal on the power network.

23. The method of claim 17, wherein processing the electromagnetic interference signal comprises:

converting the electromagnetic interference signal to a frequency domain;

identifying one or more frequencies of the electromagnetic interference signal;

summing the one or more frequencies of the electromagnetic interference signal for each of a plurality of vectors in time; and

filtering the electromagnetic interference signal.