1. A system for providing tactile feedback in a buried object locator, the system comprising:
two or more feedback components disposed in or coupled to a handle of the buried object locator and configured to provide the tactile feedback based on position information relating to determined position information of a buried physical object based on magnetic field signals received at the buried object locator that are emitted from the buried physical object;
wherein the tactile feedback includes providing a first tactile feedback output from a first tactile feedback component while providing no tactile feedback output from a second tactile feedback component to indicate a direction towards a location of the buried object.
2. The system of claim 1, wherein the tactile feedback is associated with a relative position of the user with respect to the determined location of the physical object.
3. The system of claim 2, wherein the one or more feedback components includes a plurality of feedback components configured to physically contact the user’s body.
4. The system of claim 3, wherein the plurality of feedback components are integrated with or coupled to clothing worn by the user.
5. The system of claim 1, wherein the tactile feedback indicates a direction from the user towards the physical object.
6. The system of claim 5, wherein the tactile feedback further indicates a determined amount of distance between the user and the physical object.
7. The system of claim 6, wherein the tactile feedback further indicates a determined depth of the physical object below a surface.
8. The system of claim 1, wherein the tactile feedback indicates an amount of distance between the user and the physical object.
9. The system of claim 8, wherein at least one feedback component provides one or more of time modulated, amplitude modulated, and frequency modulated tactile feedback to indicate a determined amount of distance between the user and the physical object.
10. The system of claim 9, wherein the tactile feedback further indicates a determined direction of travel towards the physical object, and at least one feedback component provides one or more of time modulated, amplitude modulated, and frequency modulated tactile feedback to indicate the direction of travel.
11. The system of claim 1, wherein the tactile feedback indicates an orientation of the user with respect to the determined location of the physical object.
12. The system of claim 1, wherein the tactile feedback indicates a determined depth of the physical object below a surface.
13. The system of claim 1, wherein at least one feedback component provides time modulated tactile feedback.
14. The system of claim 1, wherein at least one feedback component provides amplitude modulated tactile feedback.
15. The system of claim 14, wherein the at least one feedback component is configured to provide different amplitude modulated tactile feedback associated with different amounts of determined distance between the user and the physical object at different instances of time.
16. The system of claim 1, wherein at least one feedback component provides frequency modulated tactile feedback.
17. The system of claim 1, wherein at least one feedback component is configured to provide a first number of activation periods corresponding to a first number of measurement units to indicate a first determined amount of distance between the user and the physical object at a first instance in time.
18. The system of claim 17, wherein the at least one feedback component is further configured to provide a second number of activation periods corresponding to a second number of measurement units to indicate a second determined amount of distance between the user and the physical object at a second instance in time, and wherein the second number of activation periods and the second number of measurement units are both less than the first number of activation periods and the first number of measurement units when the second amount of distance is less than the first determined amount of distance, and the second number of activation periods and the second number of measurement units are greater than the first number of activation periods and the first number of measurement units when the second amount of determined distance is greater than the first amount of determined distance.
19. The system of claim 1, further comprising:
the buried object locator, wherein the buried object locator includes:
the one or more feedback components disposed within a handle of the buried object locator; and
a magnetic field locator module configured to determine the position information relating to the location of the buried object based on the magnetic fields received from the buried object.
20. The system of claim 19, further comprising:
a processing module configured to generate, based at least in part on the position information, one or more control signals, wherein the one or more feedback components provide the tactile feedback based on the control signals.
21. The system of claim 20, wherein:
a first feedback component is configured to provide first tactile feedback based on a first control signal, and a second feedback component is configured to provide no tactile feedback at a first instance of time to indicate a first direction in which the user may travel towards the object, and
the second feedback component is further configured to provide second tactile feedback based on a second control signal, and the first feedback component is further configured to provide no tactile feedback at a second instance of time to indicate a second direction in which the user may travel towards the object.
22. The system of claim 19, wherein the one or more feedback components includes a first feedback component disposed on a first side of the handle and a second feedback component disposed on a second side of the handle.
23. The system of claim 19, wherein the one or more feedback components includes an array of three or more feedback components.
24. The system of claim 19, wherein the one or more feedback components includes a plurality of feedback components configured to sequentially provide tactile feedback so as to indicate a direction of rotation in which the user may rotate in order to align the user along a path to the object.
25. The system of claim 24, wherein the tactile feedback indicates a clockwise direction of rotation about a vertical axis from the ground when the tactile feedback includes tactile feedback from a first feedback component at a first instance of time, and tactile feedback from a second feedback component at a second instance of time after the first instance of time.
26. The system of claim 19, wherein the tactile feedback indicates one or more of a determined direction in which the user may travel towards the object, an amount of determined distance between the user and the object, and a determined depth of the object below a surface.
27. The system of claim 26, wherein tactile feedback indicating the determined direction includes tactile feedback from a first feedback component and no tactile feedback from a second feedback component, and wherein tactile feedback indicating the determined amount of distance is modulated so as to provide more frequent tactile feedback as the amount of distance decreases over a time period.
28. The system of claim 19, wherein at least one feedback component provides one or more of time modulated, amplitude modulated, and frequency modulated tactile feedback.
29. The system of claim 1, wherein the position information is based at least in part on GPS location technologies.
30. The system of claim 1, wherein at least one of the feedback components is configured to provide audio feedback based on the determined position information relating to the location of the object and further based on a determined location and determined orientation of the user relative to the location of the objects.
31. The system of claim 1, wherein the tactile feedback is further based on information relating to an obstacle or hazard in the same environment of the object.
32. The system of claim 1, wherein the provided tactile feedback indicates a relative position of the buried object locator with respect to the determined location of the buried object.
33. The system of claim 1, wherein the provided tactile feedback indicates one or more of a direction towards location of the buried object, an amount of distance to the location of the buried object, and a depth of the buried object below a surface.
34. The system of claim 1, wherein the provided tactile feedback is modulated in one or more of time, frequency, and amplitude.
35. The system of claim 1, wherein one or more control signals, are generated based on the position information, and wherein a feedback component provides the tactile feedback based on the one or more control signals.
36. The system of claim 1, wherein a first feedback component is disposed on a first side of the handle and a second feedback component is disposed on a second side of the handle.
37. The system of claim 1, wherein the tactile feedback indicates an amount of distance between the user and the physical object.
38. The system of claim 1, wherein the tactile feedback indicates an orientation of the user with respect to the determined location of the physical object.
39. The system of claim 1, wherein the tactile feedback indicates a determined depth of the physical object below a surface.
40. The system of claim 39, wherein the tactile feedback further indicates a determined amount of distance between the user and the physical object.
41. The system of claim 1, wherein at least one feedback component provides time modulated tactile feedback.
42. The system of claim 1, wherein at least one feedback component provides amplitude modulated tactile feedback.
43. The system of claim 1, wherein at least one feedback component provides frequency modulated tactile feedback.
44. The system of claim 1, wherein at least one feedback component provides one or more of time modulated, amplitude modulated, and frequency modulated tactile feedback to indicate a determined amount of distance between the user and the physical object.
45. The system of claim 44, wherein the tactile feedback further indicates a determined direction of travel towards the physical object, and at least one feedback component provides one or more of time modulated, amplitude modulated, and frequency modulated tactile feedback to indicate the direction of travel.
46. The system of claim 1, wherein at least one feedback component provides a first number of activation periods corresponding to a first number of measurement units to indicate a first determined amount of distance between the user and the physical object at a first instance in time.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A method of driving a plurality of LEDs in parallel, comprising:
driving said plurality of LEDs with a first voltage in a first mode and with a second, higher voltage in a second mode;
monitoring a forward voltage drop for each LED to detect the largest said forward voltage drop; and
switching from said first mode to said second mode based on the largest said forward voltage drop.
2. The method of claim 1 wherein switching from said first mode to said second mode based on the largest said forward voltage drop comprises switching from said first mode to said second mode when said largest forward voltage drop exceeds said first voltage by an amount not greater than a predetermined threshold.
3. The method of claim 1 wherein said first voltage is the output voltage of a battery.
4. The method of claim 3 wherein said second voltage is the output of a voltage boost circuit driven by said battery.
5. The method of claim 4 further comprising a third mode wherein said plurality of LEDs is driven with a third voltage that is the output of said voltage boost circuit operating with a different boost factor than in said second mode.
6. The method of claim 1 wherein detecting said largest forward voltage drop comprises:
driving said plurality of LEDs with like currents;
monitoring the voltage drops across a corresponding plurality of resistive elements in series with said LEDs; and
identifying the smallest said voltage drop across said series resistive elements.
7. The method of claim 6, wherein switching from said first mode to said second mode comprises switching from said first mode to said second mode when said smallest said voltage drop does not exceed a predetermined threshold.
8. A method of controlling the current through an LED, comprising:
directing a first, predetermined current through a first digitally controlled variable resistance circuit;
directing a second current through a series circuit comprising said LED and a second digitally controlled variable resistance circuit having substantially a known ratio to said first variable resistance circuit;
altering a digital count based on a comparison of said first and second currents; and
simultaneously altering said first and second variable resistance circuits based on said digital count.
9. The method of claim 8 wherein altering a digital count based on a comparison of said first and second currents comprises comparing the voltage drops across said first and second variable resistance circuits, and incrementingdecrementing a digital counter based on said comparison.
10. The method of claim 9 wherein comparing the voltage drops across said first and second variable resistance circuits comprises time-averaging a voltage comparator circuit by periodically switching comparator signal polarities to null comparator offset errors from the voltage comparison operation.
11. The method of claim 10 wherein periodically switching comparator signal polarities occurs at a lower frequency than altering said digital count.
12. The method of claim 11 wherein the frequency of switching comparator signal polarities is at least an order of magnitude lower than the frequency of altering said digital count.
13. The method of claim 8 wherein each of said first and second variable resistance circuits comprises a plurality of switched, fixed resistances connected in parallel, with each said fixed resistance in said first variable resistance circuit having substantially a known ratio to a corresponding fixed resistance in said second variable resistance circuit, the two said fixed resistances being simultaneously switched into or out of said respective first and second variable resistance circuits.
14. The method of claim 13 wherein said fixed resistances in said first and second variable resistance circuits correspond to said digital counter output bits, and wherein simultaneously altering said first and second variable resistance circuits based on said digital count comprises switching corresponding fixed resistances into or out of said first and second variable resistance circuits based on said respective digital counter output bits.
15. The method of claim 13 wherein within each of said first and second variable resistance circuits, each said fixed resistance is weighted relative to said other fixed resistances in a known relationship, and wherein said digital counter output bits are weighted in said known relationship.
16. The method of claim 15 wherein said fixed resistances and said digital counter output bits are binary weighted.
17. The method of claim 13 wherein said known ratio of fixed resistances in said first variable resistance circuit to corresponding fixed resistances in said second variable resistance circuit is about 0.01.
18. A method of independently controlling the current through a plurality of LEDs connected to a voltage source, comprising:
connecting each said LED to a current control source operative to alter the resistance of a variable resistance circuit in series with said LED so as to maintain the current through said LED at a known multiple of a local reference current;
providing a master reference current to each current control source, said master reference current determined by the value of a resistive element; and
for each LED, multiplying said master reference current by a predetermined factor to generate said local reference current;
19. The method of claim 18 wherein said predetermined factor is a digital value.
20. The method of claim 18 wherein said predetermined factor varies from about to about 32.
21. A method of driving a plurality of LEDs, comprising:
connecting each LED in series with a corresponding current control circuit, and connecting the plurality of series circuits in a parallel LED circuit;
driving said parallel LED circuit with a first supply voltage in a first mode and with a second, higher supply voltage in a second mode;
providing a master reference current to each said current control source, said master reference current determined by the value of a resistive element; and
for each branch of said parallel LED circuit,
multiplying said master reference current by a predetermined factor to generate a local reference current;
directing said local reference current through a first digitally controlled variable resistance circuit;
directing a second current through a series circuit comprising said LED and a second digitally controlled variable resistance circuit having substantially a known ratio to said first variable resistance circuit;
incrementingdecrementing a digital counter based on a comparison of the voltage drops across said first and second variable resistance circuits; and
simultaneously altering said first and second variable resistance circuits based on an output of said digital counter;
whereby the current through said LED is maintained substantially at a known multiple of said local reference current.
22. The method of claim 21, wherein said predetermined factor for at least one said branch of said parallel LED circuit differs from at least one other said branch.