LIGHTING DEVICE CONTROL USING VARIABLE INDUCTOR

• US 20130043807A1
• Filed: 08/09/2012
• Published: 02/21/2013
• Est. Priority Date: 08/17/2011
• Status: Active Grant

• Current Assignee: SureFire LLC (Surefire Holdings LLC)
• Original Assignee: SureFire LLC (Surefire Holdings LLC)
• Inventors: Burayez, Ammar, Hunt, William A., Matthews, John W., Ivanov, Ivan
• Granted Patent: US 9,161,425 B2
• Time in Patent Office: Days
• US Class Current: 315/291
• CPC Class Codes: H05B 41/391 using saturable magnetic devices
• CPC Class Codes: H05B 47/165 following a pre-assigned programmed sequence; Logic control [LC]

Abstract

Various techniques are provided for implementing a lighting device variable control using a variable inductor. In various examples, the variable control may be implemented with a plurality of continuous or stepped settings. The variable control may be adjusted by a user-actuated movement of a part of the lighting device, such as the depression of a tail cap or another appropriate physical control to change the inductance of the variable inductor. An oscillating signal may be induced in a variable inductor circuit that includes the variable inductor. The oscillating signal may exhibit characteristics, such as frequency, that change with the inductance of the variable inductor. Such characteristics may be measured to determine a setting of the variable control and which may be used to adjust the brightness or other attributes of the lighting device.

Claims

1. A lighting device comprising:

a light source; and

a variable control adapted to provide a plurality of control settings, wherein the variable control comprises;

a physical control adapted to be selectively positioned by a user,

a variable inductor circuit adapted to exhibit a change in inductance based on the physical control, and

a control circuit adapted to induce an oscillating signal in the variable inductor circuit, measure the oscillating signal to determine a control setting associated with the change in inductance, and control the light source using the determined control setting, wherein the oscillating signal changes with the inductance of the variable inductor circuit.

2. The lighting device of claim 1, wherein the control circuit is adapted to adjust a brightness of the light source using the determined control setting.

3. The lighting device of claim 1, wherein the variable inductor circuit is adapted to exhibit the change in inductance in response to a position of the physical control.

4. The lighting device of claim 3, wherein the physical control is a tail cap adapted to be selectively depressed by the user.

5. The lighting device of claim 1, wherein a frequency of the oscillating signal changes with the inductance of the variable inductor circuit, wherein the control circuit is adapted to measure the frequency of the oscillating signal to determine the control setting.

6. The lighting device of claim 1, wherein the variable inductor circuit is coupled to the control circuit through one or more wires adapted to pass the oscillating signal between the variable inductor circuit and the control circuit.

7. The lighting device of claim 1, wherein the variable inductor circuit is adapted to be coupled to the control circuit through a battery adapted to pass the oscillating signal between the variable inductor circuit and the control circuit.

8. The lighting device of claim 7, further comprising the battery.

9. The lighting device of claim 7, further comprising a filter circuit adapted to filter out the oscillating signal from a voltage of the battery to generate a filtered voltage to power the light source.

10. The lighting device of claim 1, wherein the control circuit comprises:

a processor adapted to induce the oscillating signal and determine the control setting from a measurement of the oscillating signal;

an interface circuit adapted to perform the measurement of the oscillating signal; and

a memory adapted to store the control setting.

11. The lighting device of claim 1, further comprising a capacitor connected in parallel with the variable inductor circuit, wherein the control circuit is adapted to induce the oscillating signal by charging and discharging the capacitor.

12. The lighting device of claim 1, wherein the control circuit is adapted to induce a plurality of oscillating signals in the variable inductor circuit, measure the oscillating signals to determine a plurality of control settings, and control the light source using the determined control settings.

13. The lighting device of claim 1, wherein the lighting device is a flashlight.

14. A method of operating a lighting device, the method comprising:

receiving a user manipulation of a physical control that causes a variable inductor circuit to exhibit a change in inductance;

inducing an oscillating signal in the variable inductor circuit, wherein the oscillating signal changes with the inductance of the variable inductor circuit;

measuring the oscillating signal to determine a control setting associated with the change in inductance; and

controlling a light source using the determined control setting.

15. The method of claim 14, wherein the controlling the light source comprises adjusting a brightness of the light source using the determined control setting.

16. The method of claim 14, wherein the variable inductor circuit is adapted to exhibit the change in inductance in response to a position of the physical control that changes in response to the user manipulation.

17. The method of claim 16, wherein the physical control is a tail cap adapted to be selectively depressed by the user.

18. The method of claim 16, further comprising:

receiving a plurality of user manipulations that move the physical control through a plurality of positions;

inducing a plurality of oscillating signals in the variable inductor circuit;

measuring the oscillating signals to determine a plurality of control settings associated with the positions of the physical control; and

controlling a light source using the determined control settings.

19. The method of claim 14, wherein a frequency of the oscillating signal changes with the inductance of the variable inductor circuit, wherein the measuring the oscillating signal comprises measuring the frequency of the oscillating signal to determine the control setting.

20. The method of claim 14, wherein the inducing, measuring, and controlling are performed by a control circuit, wherein the variable inductor circuit is coupled to the control circuit through one or more wires, the method further comprising passing the oscillating signal between the variable inductor circuit and the control circuit through the one or more wires.

21. The method of claim 14, wherein the inducing, measuring, and controlling are performed by a control circuit, wherein the variable inductor circuit is coupled to the control circuit through a battery, the method further comprising passing the oscillating signal between the variable inductor circuit and the control circuit through the battery.

22. The method of claim 21, further comprising filtering out the oscillating signal from a voltage of the battery to generate a filtered voltage to power the light source.

23. The method of claim 14, wherein the inducing and controlling are performed by a processor, and the measuring is performed by an interface circuit.

24. The method of claim 14, wherein the inducing comprises charging and discharging a capacitor connected in parallel with the variable inductor circuit.

25. The method of claim 14, wherein the lighting device is a flashlight.