Apparatus and Methods for Interactive Illumination

• US 20110089842A1
• Filed: 10/15/2010
• Published: 04/21/2011
• Est. Priority Date: 10/15/2009
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Aldrich, Matthew, Paradiso, Joseph, Feldmeier, Mark
• Granted Patent: US 8,593,073 B2
• Time in Patent Office: Days
• US Class Current: 315/152
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/175 by remote control
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

In illustrative implementations of this invention, a lighting system comprises a plurality of LEDs, fluorescent lights, incandescent lights, a processor, a sensor node and a human-computer interface. The sensor is adapted to be moved by a user and placed in the location that a user wants to illumine. The LED lights are adapted to emit pulse-width modulated (PWM) light, controlled by signals from the processor. The lighting system is adapted to optimize parameters (such as efficacy or color rendering index) selected by the user, subject to certain constraints (such as desired illuminance or color temperature). According to principles of this invention, if a sensor is moved, attenuation may be measured and the inverse square law may be used to determine how constraints in an optimization algorithm need to be updated.

Claims

1. A lighting control system comprising, in combination:

at least one light sensor for measuring intensity of light, wherein at least part of said light is from a plurality of light sources, and

at least one processor for;

calculating the amount of said measured light intensity contributed by the respective sources,

calculating for each of said sources, respectively, the attenuation of said contributed intensity due to distance between sensor and source,

calculating the light intensity of each of said sources, respectively, needed to optimize an attribute of said plurality of sources, subject to at least one linear or non-linear constraint, and

outputting instructions for controlling said sources.

2. The system of claim 1, wherein said system is adapted to update said optimization calculations and said outputted instructions in real time, in response to said sensor being repositioned or to at least one said constraint being changed by input from a user.

3. The system of claim 1, wherein:

at least one of said sensors is an infrared sensor for measuring infrared light, and

at least one said processor calculates the intensity of visible light incident on said infrared sensor, based on said measurements of infrared light.

4. The system of claim 1, wherein

at least one of said sensors is adapted to measure the amplitude of a carrier frequency, which carrier frequency comprises part of the PWM light emitted by one of said sources, is higher than the fundamental frequency of that PWM light, and uniquely identifies that source, and

at least one said processor is adapted to calculate attenuation of said measured amplitude due to distance between sensor and source.

5. The system of claim 1, wherein

at least one said processor is adapted to output instructions for causing a substantially simultaneous change (increase or decrease) in the emitted intensity of a plurality of light sources in said system, which simultaneous change is by a known percentage, in such a way that emitted intensity is increased for some of the plurality and decreased for others in the plurality, and

at least one said processor is adapted to calculate the respective contributions of light sources to total incident intensity at a sensor.

6. The system of claim 5, wherein said increases or decreases in emitted intensity are achieved, at least in part, by altering the duty cycle of a PWM light source.

7. The system of claim 1, wherein at least one actuator is adapted to move at least one said sensor continuously or periodically through or in an area or volume.

8. The system of claim 1, wherein at least one said processor is adapted

to calculate attenuation in received signal due to a change in sensor position, and

to use said calculated attenuation in calculations that update a constraint or objective function of an optimization algorithm.

9. A lighting system comprising, in combination:

a plurality of PWM illumination sources,

at least one light sensor for measuring intensity of light, at least part of said light being from said plurality of illumination sources, and

at least one processor for;

calculating the amount of light intensity contributed by the respective said sources at a point of incidence,

calculating the light intensity of each of said sources, respectively, needed to optimize an attribute of said system, subject to at least one linear or non-linear constraint, and

outputting instructions for controlling said sources,

wherein said system is adapted to update said optimization calculations and said outputted instructions in real time, in response to said sensor being repositioned or to at least one said constraint being changed by input from a user.

10. The system of claim 9, wherein said processor is adapted to process measurements of primarily reflected light in order to update a constraint or objective function in a linear computing optimization.

11. The system of claim 9, wherein at least one of said constraints that may be so changed is a value that represents a user preference regarding lighting intensity.

12. The system of claim 9, wherein at least one of said constraints that may be so changed is a value that represents a user preference regarding color.

13. The system of claim 9, wherein at least some of PWM lighting sources comprise a polychromatic set of LED active emitters.

14. The system of claim 9, further comprising a plurality of light sensors, each of which sensors is substantially co-located with one of said PWM sources, wherein at least one said processor is adapted:

to process data regarding light intensity measurements taken by said plurality of sensors,

to calculate the respective light maps for said sources,

to superimpose said light maps on each other to calculate a model of the lighting space, and

to calculate light intensity contributed by the respective sources at a point of incidence.

15. The system of claim 9, wherein at least one said sensor is adapted for being carried or worn by a human user.

16. The system of claim 9, wherein at least one said sensor is housed with at least one infrared motion detection sensor or with at least one accelerometer.

17. The system of claim 9, wherein said attribute that is optimized is the efficacy or CRI.

18. The system of claim 9, wherein at least one actuator is adapted to move at least one said sensor continuously or periodically through or in an area or volume.

19. A method for controlling lights comprising the following steps, in combination:

using at least one sensor to measure incident intensity of light, and

using one or more processors

to calculate, for each of a plurality of PWM light sources respectively, the amount of said incident intensity that is attributable to said respective source,

to calculate for each of said sources, respectively, the attenuation of said contributed intensity due to distance between sensor and point of measurement,

to calculate the light intensity of each of said sources, respectively, needed to minimize the total power absorbed by, or total current through, said plurality of sources, subject to one or more linear or non-linear constraints, and

to output instructions for controlling said sources.

20. The method of claim 19, further comprising the step of changing at least one of said constraints in response to data inputted by a user.