Pointer position detection using light emitting diodes

• US 6,741,184 B1
• Filed: 01/11/2002
• Issued: 05/25/2004
• Est. Priority Date: 01/11/2002
• Status: Expired due to Fees

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Miller, Mark J., Lippmann, Raymond, Selby, Ronald K., Sylvester, Gail M.
• Primary Examiner(s): Crosland, Donnie L.
• Application Number:
  US10/044,536
• Time in Patent Office: 865 Days
• Field of Search: 340/815.78, 340/815.79, 340/525, 340/441, 340/459-462, 340/815.45, 362/26, 362/23, 362/32, 362/555, 362/559, 116/288, 116/291, 116/297, 250/231.11
• US Class Current: 340/815.78
• CPC Class Codes: G01D 13/26 adapted to perform a further operation, e.g. making electrical contact
• CPC Class Codes: G01D 2213/10 Drivers for gauges
• CPC Class Codes: G01R 7/06 moving-iron type
• CPC Class Codes: G08B 5/24 with indicator element moving about a pivot, e.g. hinged flap or rotating vane

Abstract

An apparatus and method sensing the absolute position of a gauge. A pointer having a predefined rotation with a circular travel pattern. At least one light emitting diode that generates an optical signal. An optical sensor placed in a fixed position along the circular travel pattern of the pointer. A pointer driver for driving the pointer.

Claims

1. An apparatus for accurately sensing the absolute position of a gauge, comprising:

at least one pointer having a predefined travel pattern;

at least one light emitting diode that generates an optical signal;

at least one optical sensor placed in a fixed position along the travel pattern of the pointer; and

a pointer driver for driving the pointer,

wherein the at least one light emitting diode further includes a first light emitting diode which emits infrared light and a second light emitting diode which emits visible light.

2. The apparatus according to claim 1, further comprising a pointer hub that captures the optical signal from the first and second light emitting diodes and transmits the optical signal to the pointer.

3. The apparatus according to claim 1, further comprising a microprocessor that receives the optical signal from the optical sensor.

4. The apparatus according to claim 3, wherein the microprocessor further comprises a software algorithm for determining the maximum sensed optical signal.

5. The apparatus according to claim 1, further comprising a circuit for synchronizing and pulsing the optical signal.

6. The apparatus according to claim 5, wherein the circuit further comprises a voltage source, a photodiode, a pre-amp, a buffer, a comparator, a signal processing circuit, a voltage output, an oscillator, a timing generator, and a light emitting diode driver.

7. The apparatus according to claim 1, wherein the predefined rotation of the pointer is greater than 360 degrees.

8. The apparatus according to claim 1, wherein the first light emitting diode emits pulsed infrared light and the second light emitting diode emits constant visible light.

9. The apparatus according to claim 1, wherein the second light emitting diode emits pulsed visible light.

10. The apparatus according to claim 1, wherein the optical sensor further comprises a filter to reduce the sensitivity of ambient light.

11. The apparatus according to claim 1, wherein the optical sensor further comprises a lens applied over the sensor to focus the optical signal emitted from the pointer.

12. The apparatus according to claim 1, further comprising a graphics region.

13. The apparatus according to claim 12, wherein the graphics region further comprises a visual alarm.

14. The apparatus according to claim 1, further comprising an audible alarm.

15. The apparatus according to claim 2, wherein the pointer hub is a lightpipe.

16. The apparatus according to claim 1, wherein the predefined rotation of the pointer is less than 360 degrees.

17. The apparatus according to claim 1, wherein the predefined rotation of the pointer is 360 degrees.

18. An apparatus for accurately determining and correcting the indicating position of a gauge, comprising:

a pointer having a predefined rotation that has a circular travel pattern;

at least one light emitting diode;

an optical signal generated by the at least one light emitting diode;

at least one pointer hub that captures and transmits the optical signal down the length of the pointer;

an optical sensor placed in a fixed position along the circular travel pattern of the pointer;

a filter attached to the optical sensor;

a lens attached to the optical sensor;

a microprocessor that receives the optical signal from the optical sensor;

a circuit for synchronizing and pulsing the optical signal; and

a stepper motor for driving the pointer that is controlled by the microprocessor.

19. The apparatus according to claim 18, wherein the microprocessor further comprises a software algorithm for determining the maximum sensed optical signal.

20. The apparatus according to claim 18, wherein the circuit further comprises a voltage source, a photodiode, a pre-amp, a buffer, a comparator, a signal processing circuit, a voltage output, an oscillator, a timing generator, and a light emitting diode driver.

21. The apparatus according to claim 18, wherein said at least one light emitting diode includes first and second light emitting diodes, wherein said first light emitting diode emits a constant infrared light and the second light emitting diode emits a constant visible light.

22. The apparatus according to claim 20, wherein said at least one light emitting diode includes first and second light emitting diodes, wherein said first light emitting diode generates a pulsed infrared light and the second light emitting diode emits a constant visible light.

23. The apparatus according to claim 20, wherein the at least one light emitting diode emits a pulsed visible light.

24. The apparatus according to claim 18, wherein the pointer hub is a lightpipe.

25. The apparatus according to claim 18, further comprising a graphics region.

26. The apparatus according to claim 25, wherein the graphics region further comprises a visual alarm.

27. The apparatus according to claim 18, further comprising an audible alarm.

28. The apparatus according to claim 18, wherein the predefined rotation of the pointer is less than 360 degrees.

29. The apparatus according to claim 18, wherein the predefined rotation of the pointer is 360 degrees.

30. The apparatus according to claim 18, wherein the predefined rotation of the pointer is greater than 360 degrees.

31. An apparatus for accurately determining and correcting the indicating position of a gauge, comprising:

a first pointer having a predefined rotation that has a circular travel pattern;

a second pointer having a predefined rotation that has a circular travel pattern;

at least one light emitting diode;

an optical signal generated by the light emitting diode;

at least one pointer hub that captures and transmits the optical signal down the length of the first and second pointer;

an optical sensor placed in a fixed position along the circular travel pattern of the first and second pointer;

a filter attached to the optical sensor;

a lens attached to the optical sensor;

a microprocessor that receives the optical signal from the optical sensor;

a circuit for synchronizing and pulsing driving the optical signal; and

a stepper motor for driving the first and second pointer that is controlled by the microprocessor.

32. The apparatus according to claim 31, wherein the microprocessor further comprises a software algorithm for determining the maximum sensed optical signal.

33. The apparatus according to claim 31, wherein the circuit further comprises a voltage source, a photodiode, a pre-amp, a buffer, a comparator, a signal processing circuit, a voltage output, an oscillator, a timing generator, and a light emitting diode driver.

34. The apparatus according to claim 31, wherein the first light emitting diode emits a constant infrared light and the second light emitting diode emits a constant visible light.

35. The apparatus according to claim 33, wherein the first light emitting diode generates a pulsed infrared light and the second light emitting diode emits a constant visible light.

36. The apparatus according to claim 33, wherein the light emitting diode emits a pulsed visible light.

37. The apparatus according to claim 31, wherein the pointer hub is a lightpipe.

38. The apparatus according to claim 31, further comprising a graphics region.

39. The apparatus according to claim 38, wherein the graphics region further comprises a visual alarm.

40. The apparatus according to claim 31, further comprising an audible alarm.

41. The apparatus according to claim 31, wherein the predefined rotation of the pointer is less than 360 degrees.

42. The apparatus according to claim 31, wherein the predefined rotation of the pointer is 360 degrees.

43. The apparatus according to claim 31, wherein the predefined rotation of the pointer is greater than 360 degrees.

44. A method for sensing the absolute position of a gauge, the gauge having a pointer, at least one light emitting diode, an optical signal, at least one pointer hub, an optical sensor placed in a fixed position along the circular travel pattern of the pointer, a microprocessor that receives the optical signal from the optical sensor, a circuit, and a stepper motor, comprising the steps of:

generating an optical signal from the light emitting diode;

transmitting an optical signal through the pointer hub;

sensing an optical signal at the sensor;

calculating an error between an actual sensed position of the pointer and a former assumed position of the pointer in the microprocessor;

zeroing the stepper motor from the calculated error of the microprocessor; and

transmitting a stepper signal to the stepper motor.

45. The method according to claim 44, wherein the optical signal generating step is performed by the circuit.

46. The method according to claim 45, wherein the optical signal is pulsed.

47. The method according to claim 46, further comprising the step of synchronizing the sensed optical signal with the generated optical signal.