Method and apparatus of position tracking and detection of user input information

1. An apparatus, comprising:

a calibration input unit; and

at least one sensor capable of detecting a user's movement of an input element;

wherein the calibration input unit comprises a button that is disposed on a rigid arm and is moveable by movement of the rigid arm from a stored position within a housing of the sensor to an outward position at a known position relative to the sensor, wherein the button is coupled to the at least one sensor and is selectable by the user using the input element;

wherein the sensor is adapted to sense the position of the input element when the input element is on the button; and

wherein the calibration input unit is configured to perform a calibration procedure by comparing a known position of the button relative to the sensor with a sensed position of the button as detected by the input element being placed on the button.

2. The apparatus of claim 1 , wherein the input element is a passive pen-shaped writing utensil that does not contain any electronic components.

3. The apparatus of claim 2 , wherein the button is selected by a pressing motion performed via the input element, and wherein the calibration input unit measures the position of the input element.

4. The apparatus of claim 3 , wherein the calibration input unit determines whether the calculated position of the input element matches a known position of the calibration unit button, and, if so, then the calibration procedure is complete, and, if not, the calibration input unit adjusts a calculation algorithm used to determine the position of the calibration button.

5. The apparatus of claim 2 , wherein the apparatus further comprises a calibration arm that extends from the sensor, and which is capable of being extracted from the sensor via a folding movement, wherein the calibration arm comprises the button.

6. The apparatus of claim 1 , wherein selection of the button by the input element establishes a position of the input element at the button relative to the sensor.

7. The apparatus of claim 1 , wherein the input element comprises a transmitter that emits ultrasound burst signals which are received at the sensor.

8. The apparatus of claim 7 , wherein the at least one sensor detects the arrival time of the burst and compares it to the arrival time measured at another sensor to determine the position of the input element.

9. The apparatus of claim 8 , wherein the position of the input element is performed via a triangulation algorithm.

10. The apparatus of claim 8 , wherein the at least one calibration unit is further configured to determine the position of the at least one sensor based on the position of said another sensor.

11. A method, comprising:

positioning at least one sensor that detects a user's movement of an input element;

wherein performing the calibration procedure comprises extracting a rigid arm from a housing of the at least one sensor to an outward known position relative to the at least one sensor;

sensing, by the sensor, the position of the input element when the input element is on the button; and

wherein selection of the button by the input element establishes a position of the input element at the button relative to the sensor.

12. The method of claim 11 , wherein the input element is a passive pen-shaped writing utensil that does not contain any electronic components.

13. The method of claim 12 , wherein the button is selected by a pressing motion performed via the input element, and wherein the calibration input unit measures the position of the input element.

14. The method of claim 13 , further comprising determining whether the calculated position of the input element matches a known position of the calibration unit button via the calibration input unit, and, if so, then the calibration procedure is complete, and, if not, the calibration input unit further comprises adjusting a calculation algorithm used to determine the position of the calibration button.

15. The method of claim 12 , further comprising extending a calibration arm from the sensor, which is capable of being extracted from the sensor via a folding movement, and wherein the calibration arm comprises the button.

16. The method of claim 11 , wherein selection of the button by the input element establishes a position of the input element at the button relative to the sensor.

17. The method of claim 11 , further comprising emitting ultrasound burst signals, via the input element, which are received at the sensor.

18. The method of claim 17 , further comprising detecting the arrival time of the burst and comparing it to the arrival time measured at another sensor to determine the position of the input element.

19. The method of claim 18 , wherein the position of the input element is performed via a triangulation algorithm.

20. The method of claim 18 , further comprising determining the position of the at least one sensor based on the position of said another sensor.